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Tony Pearson is a Master Inventor, Senior IT Architect and Event Content Manager for [IBM Systems for IBM Systems Technical University] events. With over 30 years with IBM Systems, Tony is frequent traveler, speaking to clients at events throughout the world.
Lloyd Dean is an IBM Senior Certified Executive IT Architect in Infrastructure Architecture. Lloyd has held numerous senior technical roles at IBM during his 19 plus years at IBM. Lloyd most recently has been leading efforts across the Communication/CSI Market as a senior Storage Solution Architect/CTS covering the Kansas City territory. In prior years Lloyd supported the industry accounts as a Storage Solution architect and prior to that as a Storage Software Solutions specialist during his time in the ATS organization.
Lloyd currently supports North America storage sales teams in his Storage Software Solution Architecture SME role in the Washington Systems Center team. His current focus is with IBM Cloud Private and he will be delivering and supporting sessions at Think2019, and Storage Technical University on the Value of IBM storage in this high value IBM solution a part of the IBM Cloud strategy. Lloyd maintains a Subject Matter Expert status across the IBM Spectrum Storage Software solutions. You can follow Lloyd on Twitter @ldean0558 and LinkedIn Lloyd Dean.
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Continuing my business trip through Asia, I have left Chengdu, China, and am now in Kuala Lumpur, Malaysia.
On Sunday, a colleague and I went to the famous Petronas Twin Towers, which a few years ago were officially the tallestbuildings in the world. If you get there early enough in the day, and wait in line for a few hours, you can get a ticket permitting you to go up to the "Skybridge" on the 41st floor that connects the two buildings. The views are stunning, and I am glad to have done this.(If you are afraid of heights, get cured by facing your fears with skydiving)
You would think that a question as simple as "Which is the tallest building in the world?" could easily be answered, given that buildings remain fixed in one place and do not drastically shrink or get taller over time or weather conditions, and the unit of height, the "meter", is an officially accepted standard in all countries, defined as the distance traveled by light in absolute vacuum in 1/299,792,458 of a second.
The controversy stems around two key areas of dispute:
What constitutes a building?
A building is a structure intended for continuous human occupancy, as opposed to the dozens ofradio and television broadcasting towers which measure over 600 meters in height. The Petronas Twin Towers is occupied by a variety of business tenants and would qualify as a building. Radio and Television towers are not intended for occupation, and should not be considered.
Where do you start measuring, and where do you stop?
Since 1969, the height was generally based on a building's height from the sidewalk level of the main entrance to the architectural top of the building. The "architectural top" included towers, spires (but not antennas), masts or flagpoles. Should the measurements be only to the top to the highest inhabitable floor?
What if the building has many more floors below ground level? What if the building exists in a body of water, should sidewalk level equate to water level, and at low tide or high tide? (Laugh now, but this might happen sooner than you think!)
To bring some sanity to these comparisons, the Council on Tall Buildings and Urban Habitat has tried to standardize the terms and definitions to makecomparisons between buildings fair. Why does all this matter whose building is tallest? It matters in twoways:
People and companies are willing to pay more to be a tenant in tall towers, affording a luxurious bird's-eyeview to impress friends, partners and clients, and so the rankings can influence purchase or leasing prices of floorspace in these buildings.
Architects and engineers involved in building these structures want to list these on their resume.These buildings are an impressive feat of engineering, and the teams involved collaborate in a global mannerto accomplish them. If an architecture or engineeering company can build the world's tallest building, you can trust themto build one for you. The rankings can help drive revenues in generating demand for services and offerings.
What does any of this have to do with storage? Two weeks ago, IBM and the Storage Performance Councilanswered the question "Which is the fastest disk system?" with apress release. Customers thatcare about performance of their most mission critical applications are often willing to pay a premium to run theirapplications on the fastest disk system, and the IBM System Storage SAN Volume Controller, built through aglobal collaboration of architects and engineers across several countries, is (in my opinion at least) an impressive feat of storage engineering.
"The murals in restaurants are on par with the food in museums." --- Peter De Vries
The quote above applies to blogs as well. Those about competitive products of which the blogger has little to no hands-on experience tend to be terribly misleading or technically inaccurate. We saw this last month as Sun Microsystems' Jeff Savit tried to discuss the IBM System z10 EC mainframe.
This time, it comes from EMC bloggers discussing NetApp equipment, and by association, IBM System Storage N series gear.I was going to comment on the ridiculous posts by fellow bloggers from EMC about SnapLock compliance feature on the NetApp, but my buddies at NetApp had already done this for me, saving me the trouble.
The hysterical nature of writing from EMC, and the calm responses from NetApp, speak volumes about the culturesof both companies.
The key point is that none of the "Non-erasable, Non-Rewriteable" (NENR) storage out there are certified as compliant by any government agency on the planet. Governments just aren't in the business of certifying such things. The best you can get is a third-party consultant, such as [Cohasset Associates], to help make decisions that are best for each particular situation.
In addition to SnapLock on N series, IBM offers the [IBM System Storage DR550], WORM tape and optical systems, all of which have been deemed compliant to the U.S. Securities and Exchange Commission [SEC 17a-4] federal regulations by Cohasset Associates. For medical patient records and images like X-rays, IBM offers the Grid Medical Archive Solution [GMAS]designed to meet the requirements of the U.S. Health Insurance Portability and Accountability Act[HIPAA].For other government or industry regulations, consult with your legal counsel.
Chris Anderson, of Wired magazine, wrote a great article called The Long Tail.
This article became a book by the same name published earlier this year, and I just discovered it on a recent visit to Second Life. A lot of IBMers are now alsoSecond Lifers, and I suspect it is just a matter of time before we are conductingour customer briefings there, and getting our year-end bonuses paid directly in Linden bucks.(Those of you not familiar with Second Life can watch this 3-minute video fromthe folks at Text100)
Anyways, the Long Tail describes the new economy of entertainment thanks to digitalstorage. Here are some of the key insights.
In the past, entertainment was all about hits: hit songs, hit movies,hit novels, and this was primarily because of the economic realities restricted byphysical space. Chris writes: "An average movie theater will not show a film unless it can attract at least 1,500 people over a two-week run; that's essentially the rent for a screen. An average record store needs to sell at least two copies of a CD per year to make it worth carrying; that's the rent for a half inch of shelf space."
Things have changed. To drive the point home, Robbie Vann-Adibe (CEO of eCast), poses the trick question"What percentage of the top 10,000 titles in any online media store (Netflix, iTunes, Amazon, or any other) will rent or sell at least once a month?" The answer will surprise you. Write down your guess first, then go read here. His digital jukeboxes are able to play from a list of150,000 songs, not the few hundred you'd find at the Tap Room which is rated as having the best jukebox in Tucson.
The phenomenon is not just limited to music. "Take books," Chris writes, "The average Barnes & Noble carries 130,000 titles. Yet more than half of Amazon's book sales come from outside its top 130,000 titles. Consider the implication: If the Amazon statistics are any guide, the market for books that are not even sold in the average bookstore is larger than the market for those that are..."
This has incredible implications for the storage industry. For one, content providers are going to dig deep into their archives to digitize and deliver "long tail" offerings. If they don't have a deep archive, many will start to build one. Second, the need to search through that large volume of content will become more critical. Classifying and indexing with the appropriate tags and metadata will be an important task.
Avi Bar-Zeeb of RealityPrime has an interesting post aboutHow Google Earth [really] Works.Normally, people who are very knowledgeable in a topic have a hard time describing concepts in basic terms. Avi was one of the co-founders of Keyhole, the company that built the predecessor for Google Earth, and also worked with Linden Lab for its 3D rendering it its virtual world, so he certainly knows what he is talking about. While he sometimes drops down into techno-talk about patents, the post overall is a good read.
It is perhaps human nature to be curious on how things are put together and how they function, leading to the popularity of web sites like www.howstuffworks.com that cover a wide range of topics.
Many things can be used without understanding their internal inner workings. You can put on a pair of blue jeans without knowing how the cotton was made into denim fabric; lace up your favorite pair of running shoes without understanding the chemical make-up of the plastic that cushions your feet; or drink a glass of beer after your five mile run without knowing how alcohol is processed by your liver.
For technology, however, some people insist they need to know how it works in order for them to get the most use of it. When shopping for a car, for example, a guy might look under the hood, and ask questions about how the engine works, while his wife sits inside the vehicle, counting cup holders and making sure the radio has all the right buttons.
Not all technology suffers from need-to-know-itis. For example, the Apple iPod music player and the Canon PowerShot digital camera, are both just disk systems that read and write data, with knobs and dials on one end, and ports for connectivity on the other. Everyone just asks how to use their controls, and might read the manual to understand how to connect the cables. Few people who use these devices ask how they work before they buy them.
Other disk systems, the kind designed for data centers for the medium and large enterprise, apparently aren't there yet. Storage admins who might happily own both an iPod player and a PowerShot camera, insist they need to know how the technologies inside various storage offerings work. Is this just curiosity talking? Or are there some tasks like configuration, tuning, and support that just can't be done without this knowledge? Does knowing the inner workings somehow make the job more enjoyable, easier, or performed with less stress?
I'm curious what you think, send me a comment on this.
This week is Thanksgiving holiday in the USA, so I thought a good theme would be things I am thankful for.
I'll start with saying that I am thankful EMC has finally announcedAtmos last week. This was the "Maui" part of the Hulk/Maui rumors we heard over a year ago. To quickly recap, Atmos is EMC's latest storage offeringfor global-scale storage intended for Web 2.0 and Digital Archive workloads. Atmos can be sold as just software, or combined with Infiniflex,EMC's bulk, high-density commodity disk storage systems. Atmos supports traditionalNFS/CIFS file-level access, as well as SOAP/REST object protocols.
I'm thankful for various reasons, here's a quick list:
It's hard to compete against "vaporware"
Back in the 1990s, IBM was trying to sell its actual disk systems against StorageTek's rumored "Iceberg" project. It took StorageTek some four years to get this project out,but in the meantime, we were comparing actual versus possibility. The main feature iswhat we now call "Thin Provisioning". Ironically, StorageTek's offering was not commercially successful until IBM agreed to resell this as the IBM RAMAC Virtual Array (RVA).
Until last week, nobody knew the full extent of what EMC was going to deliver on the many Hulk/Maui theories. Severalhinted as to what it could have been, and I am glad to see that Atmos falls short of those rumored possibilities. This is not to say that Atmos can't reach its potential, and certainly some of the design is clever, such as offering native SOAP/REST access.
Instead, IBM now can compare Atmos/Infiniflex directly to the features and capabilities of IBM's Scale Out File Services [SoFS], which offers a global-scale multi-site namespace with policy-based data movement, IBM System Storage Multilevel Grid Access Manager[GAM] that manages geographical distrubuted information,and IBM [XIV Storage System] that offers high-density bulk storage.
Web 2.0 and Digital Archive workloads justify new storage architectures
When I presented SoFS and XIV earlier this year, I mentioned they were designed forthe fast-growing Web 2.0 and Digital Archive workloads that were unique enough to justify their own storage architectures. One criticism was that SoFS appeared to duplicate what could be achieved with dozens of IBM N series NAS boxes connected with Virtual File Manager (VFM). Why invent a new offering with a new architecture?
With the Atmos announcement, EMC now agrees with IBM that the Web 2.0 and DigitalArchive workloads represent a unique enough "use case" to justify a new approach.
New offerings for new workloads will not impact existing offerings for existing workloads
I find it amusing that EMC is quickly defending that Atmos will not eat into its DMXbusiness, which is exactly the FUD they threw out about IBM XIV versus DS8000 earlier this year. In reality, neither the DS8000 nor the DMX were used much for Web 2.0 andDigital Archive workloads in the past. Companies like Google, Amazon and others hadto either build their own from piece parts, or use low-cost midrange disk systems.
Rather, the DS8000 and DMX can now focus on the workloads they were designed for,such as database applications on mainframe servers.
Cloud-Oriented Storage (COS)
Just when you thought we had enough terminology already, EMC introduces yet another three-letter acronym [TLA]. Kudos to EMC for coining phrases to help move newconcepts forward.
Now, when an RFP asks for Cloud-oriented storage, I am thankful this phrase will help serve as a trigger for IBM to lead with SoFS and XIV storage offerings.
Digital archives are different than Compliance Archives
EMC was also quick to point out that object-storage Atmos was different from theirobject-storage EMC Centera. The former being for "digital archives" and the latter for"compliance archives". Different workloads, Different use cases, different offerings.
Ever since IBM introduced its [IBM System Storage DR550] several years ago, EMC Centera has been playing catch-up to match IBM'smany features and capabilities. I am thankful the Centera team was probably too busy to incorporate Atmos capabilities, so it was easier to make Atmos a separate offering altogether. This allows the IBM DR550 to continue to compete against Centera's existingfeature set.
Micro-RAID arrays, logical file and object-level replication
I am thankful that one of the Atmos policy-based feature is replicating individualobjects, rather than LUN-based replication and protection. SoFS supports this forlogical files regardless of their LUN placement, GAM supports replication of files and medical images across geographical sites in the grid, and the XIV supports this for 1MBchunks regardless of their hard disk drive placement. The 1MB chunk size was basedon the average object size from established Web 2.0 and DigitalArchive workloads.
I tried to explain the RAID-X capability of the XIV back in January, under muchcriticism that replication should only be done at the LUN level. I amthankful that Marc Farley on StorageRap coined the phrase[Micro-RAID array] to helpmove this new concept further. Now, file-level, object-level and chunk-level replication can be considered mainstream.
Much larger minimum capacity increments
The original XIV in January was 51TB capacity per rack, and this went up to 79TB per rack for the most recent IBM XIV Release 2 model. Several complained that nobody would purchase disk systems at such increments. Certainly, small and medium size businessesmay not consider XIV for that reason.
I am thankful Atmos offers 120TB, 240TB and 360TB sizes. The companies that purchasedisk for Web 2.0 and Digital Archive workloads do purchase disk capacity in these large sizes. Service providers add capacity to the "Cloud" to support many of theirend-clients, and so purchasing disk capacity to rent back out represents revenue generating opportunity.
Renewed attention on SOAP and REST protocols
IBM and Microsoft have been pushing SOA and Web Services for quite some time now.REST, which stands for [Representational State Transfer] allows static and dynamic HTML message passing over standard HTTP.SOAP, which was originally [Simple Object Access Protocol], and then later renamed to "Service Oriented Architecture Protocol", takes this one step further, allowingdifferent applications to send "envelopes" containing messages and data betweenapplications using HTTP, RPC, SMTP and a variety of other underlying protocols.Typically, these messages are simple text surrounded by XML tags, easily stored asfiles, or rows in databases, and served up by SOAP nodes as needed.
It's hard to show leadership until there are followers
IBM's leadership sometimes goes unnoticed until followerscreate "me, too!" offerings or establish similar business strategies. IBM's leadership in Cloud and Grid computing is no exception.Atmos is the latest me-too product offering in this space, trying pretty muchto address the same challenges that SoFS and XIV were designed for.
So, perhaps EMC is thankful that IBM has already paved the way, breaking throughthe ice on their behalf. I am thankful that perhaps I won't have to deal with as much FUD about SoFS, GAM and XIV anymore.
"Our survey data shows that over the past 12 months, more firms have bought their storage from a single vendor. While this might not be for everyone, it's worth serious consideration for your environment. Maybe you won't get the best price per gigabyte every time, but you'll probably save money in the long run because of simpler management, increased staff specialization, increased capacity utilization, and better customer service."
A Forrester survey of 170 companies ranging from SMBs to large enterprises in North America and Europe found that more than 80 percent bought their primary storage from one vendor over the last year. That includes 64 percent of the companies with more than 500 TB of raw storage.
The report, written by analyst Andrew Reichman, says using more than one primary storage vendor can make it more complex to manage, provision and support the storage environment. And while using multiple vendors can often bring better pricing, buying from one vendor can result in volume discounts.
“You may have tried to contain costs by forcing multiple incumbent vendors to continuously compete against each other, with price as the primary differentiator,” Reichman writes. “This strategy can reduce prices and limit vendor lock-in, but it can also lead to management complexity and poor capacity utilization.”
The report recommends keeping things simple by and using fewer vendors when possible. However, that advice comes with several caveats: buying all storage from one vendor means taking the bad with the good, and some vendors’ product families differ so much “they may as well come from different vendors.”
As if by coincidence, fellow blogger from EMC Chuck Hollis gives his reflections on this same topic. Here's an excerpt:
When it comes to buying storage (or any infrastructure technology, for that matter), there seem to be two camps:
Best-of-breed (i.e. multivendor): -- buy what's best, get the best price, keep all the vendors on their toes, etc. etc.
Single vendor: primarily use one vendor's offerings, and hold them accountable for the outcome.
If Chuck had said "multivendor" versus "single vendor", then that would have been a true dichotomy, but interestinglyhe equates best-of-breed with a multivendor approach. Let's consider two examples:
Disk from one vendor, Tape from another
Here is a multivendor strategy, and if you have a clear idea of what best-of-breed means to you, then you couldpick the best disk in the market, and the best tape in the market. However, I don't think this keeps either vendor"on their toes", or helps you negotiate lower prices by threatening to switch to the other vendor. In shops likethis, the staffing usually matches, so there are disk administration and tape operations, with little or no overlap, andlittle or no interest in retraining to use a new set of gear. It is true that disk-based VTL could be used where real tape libraries are used, but this may not be enough to threaten your existing vendors that you will switch all your disk to tape, or all your tape to disk.
One could argue that the vendor that sells the besttape could be the exact same vendor that sells the best disk. In this case, your multivendor strategy would actuallywork against you, forcing you away from one of your best-of-breed choices.
Disk and Tape from one vendor for some workloads, Disk and Tape from another vendor for other workloads
Here is a different multivendor strategy. Having disk and tape for the same vendor allows you to take advantageof possible synergies. The IT staff knows how to use the products from both vendors. This strategy does let you keep your vendors "on their toes". You can legitimately threaten to shift your budget from one vendor over another.However, whatever your definition of best-of-breed is, chances are the product from one vendor is, and the other vendor is not. Both meet some lowest common denominator, meeting some minimum set of requirements, which would allow you to swap out one for the other.
I guess I look at it differently. The equipment in your data center should be thought of as a team. Do your servers, storage and software work well together?
While Americans like to celebrate the accomplishments of individual musicians, athletes or executives, it is actually bands that compete against other bands, sports teams that compete against other sport teams, and companies that compete against other companies. Teamwork in the data center is not just for the people who work there, but also for the IT equipment. Just as a new incoming athlete may not get along well with teammates, shiny new equipment may not get along with your existing gear. Conversely, your existing infrastructure may not let the talents or features of your new equipment shine through.
Putting together the best parts from different teams might serve as a great diversion for those who enjoy["fantasy football"], it may not be the best approach for the data center. Instead, focus on managing your data center as a team, perhaps with theuse of IBM TotalStorage Productivity Center to minimize the heterogeneity of your different equipment. Pick an ITvendor that sells "team players" for your servers, storage and software, with broad support for interoperability and compatibility.
To get beyond the simple statistics of vendor popularity, we looked at the number and combinations of vendors with which enterprises work. Many were customers of one or two storage providers, but the rest were customers of up to six storage providers. More than one-third were customers of systems vendors only, bypassing storage specialists.
Comparisons between solutions vendors and storage component vendors are not new. One could argue that this can be compared to supermarkets and specialty shops.
Supermarkets offer everything you need to prepare a meal. You can buy your meat, bread, cheese,and extras all with one-stop shopping. In a sense, IBM, HP, Sun and Dell are offering this to clients who prefer this approach. Not surprisingly, the two leaders in overall storage hardware,IBM and HP, are also the two best to offer a complete set of software, services, servers and storage.
IBM and HP are also the leaders in tape.While Forrester reports that many large enterprises in North America prefer to buy diskfrom storage specialists, others have found that customers prefer to buy their tape from solution providers. Recently, Byte and Switch reports thatLTO Hits New Milestones,where the LTO consortium (IBM, HP, and Quantum) have collectively shipped over 2 million LTO tape drives, and over 80 million LTO tape cartridges. Perhaps this is because tape is part of an overallbackup, archive or space management solution, and customers trust a solution vendor overa storage specialist.
Where possible, IBM brings synergy between its servers and storage. For example, we justannounced the IBM BladeCenter Boot Disk System, a 2U high unit that supports up to 28 blade servers, ideal for applications running under Windows or Linux, and helping to reduce the energy consumption for thoseinterested in a "Green" data center.
Some people prefer buying their meat at the slaughterhouse, bread at the French pastry shop, andso on. Storage specialists focus on just storage, leaving the rest of the solution, like servers,to be purchased separately from someone else. Storage vendors like NetApp, EMC, HDS and othersoffer storage components to customers that like to do their own "system integration", or to thosethat are large enough to hire their own "systems integrator".
Storage specialists recognize that not everybody is a "specialty shop" shopper.HDS has done well selling their disk through solution vendorslike HP and Sun. EMC sells its gear through solution vendor Dell.
Interestingly, I have met clients who prefer to buy IBM System Storage N series from IBM, becauseIBM is a solution vendor, and others that prefer to buy comparable NetApp equipment directly fromNetApp, because they are a storage component vendor.
I mostly buy my groceries at a supermarket, buthave, on occasion, bought something from the local butcher, baker or candlestick maker. And if you are ever in Tucson, you might be able to find Mexican tamalessold by a complete stranger standing outside of a Walgreens pharmacy, the ultimate extreme of specialization. You can get a dozen tamales for tenbucks, and in my experience they are usually quite good. Theoretically, if you get sick, or they don't taste right, you have no recourse, and will probably never see that stranger again to complain to.(And no, before I get flamed, I am not implying any major vendor mentioned above is like this tamale vendor)
Of course, nothing is starkly black and white, and comparisons like this are just to help provide context and perspective,but if you are looking to have a complete IT solutionthat works, from software and servers to storage and financing, come to the vendor you can trust, IBM.
Continuing my ongoing discussion on Solid State Disk (SSD), fellow blogger BarryB (EMC) points out in his [latest post]:
Oh – and for the record TonyP, I don't think I ever said EMC was using a newer or different EFDs than IBM. I just asserted that EMC knows more than IBM about these EFDs and how they actually work a storage array under real-world workloads.
(Here "EFD" is refers to "Enterprise Flash Drive", EMC's marketing term for Single Layer Cell (SLC) NAND Flash non-volatile solid-state storage devices. Both IBM and EMC have been selling solid-state storage for quite some time now, but EMC felt that a new term was required to distinguish the SLC NAND Flash devices sold in their disk systems from solid-state devices sold in laptops or blade servers. The rest of the industry, including IBM, continues to use the term SSD to refer to these same SLC NAND Flash devices that EMC is referring to.)
Although STEC asserts that IBM is using the latest ZeusIOPS drives, IBM is only offering the 73GB and 146GB STEC drives (EMC is shipping the latest ZeusIOPS drives in 200GB and 400GB capacities for DMX4 and V-Max, affording customers a lower $/GB, higher density and lower power/footprint per usable GB.)
Here is where I enjoy the subtleties between marketing and engineering. Does the above seem like he is saying EMC is using newer or different drives? What are typical readers expected to infer from the statement above?
That there are four different drives from STEC, in four different capacities. In the HDD world, drives of different capacities are often different, and larger capacities are often newer than those of smaller capacities.
That the 200GB and 400GB are the latest drives, and that 73GB and 146GB drives are not the latest.
That STEC press release is making false or misleading claims.
Uncontested, some readers might infer the above and come to the wrong conclusions. I made an effort to set the record straight. I'll summarize with a simple table:
Usable (conservative format)
Usable (aggressive format)
So, we all agree now that the 256GB drives that are formatted as 146GB or 200GB are in fact the same drives, that IBM and EMC both sell the latest drives offered by STEC, and that the STEC press release was in fact correct in its claims.
I also wanted to emphasize that IBM chose the more conservative format on purpose. BarryB [did the math himself] and proved my key points:
Under some write-intensive workloads, an aggressive format may not last the full five years. (But don't worry, BarryB assures us that EMC monitors these drives and replaces them when they fail within the five years under their warranty program.)
Conservative formats with double the spare capacity happen to have roughly double the life expectancy.
I agree with BarryB that an aggressive format can offer a lower $/GB than the conservative format. Cost-conscious consumers often look for less-expensive alternatives, and are often willing to accept less-reliable or shorter life expectancy as a trade-off. However, "cost-conscious" is not the typical EMC targeted customer, who often pay a premiumfor the EMC label. To compensate, EMC offers RAID-6 and RAID-10 configurations to provide added protection. With a conservative format, RAID-5 provides sufficient protection.
(Just so BarryB won't accuse me of not doing my own math, a 7+P RAID-5 using conservative format 146GB drives would provide 1022GB of capacity, versus 4+4 RAID-10 configuration using aggressive format 200GB drives only 800GB total.)
In an ideal world, you the consumer would know exactly how many IOPS your application will generate over the next five years, exactly how much capacity you will require, be offered all three drives in either format to choose from, and make a smart business decision. Nothing, however, is ever this simple in IT.
Continuing my week in Chicago, for the IBM Storage Symposium 2008, I attended several sessions intended to answer the questions of the audience.
In an effort to be cute, the System x team have a "Meet the xPerts" session at their System x and BladeCenter Technical Conference, so the storage side decided to do the same. Traditionally, these have been called "Birds of a Feature", "Q&A Panel", or "Free-for-All". They allow anyone to throw out a question, and have the experts in the room, either
IBM, Business Partner or another client, answer the question from their experience.
Meet the Experts - Storage for z/OS environments
Here were some of the questions answered:
I've seen terms like "z/OS", "zSeries" and "System z" used interchangeably, can you help clarify what this particular session is about?
IBM's current mainframe servers are all named "System z", such as our System z9 or System z10. These replace the older zSeries models of hardware. z/OS is one of the six operating systems that run on this hardware platform. The other five are z/VM, z/VSE, z/TPF, Linux and OpenSolaris. The focus of this session will be storage attached and used for z/OS specifically, including discussions of Omegamon and DFSMS software products.
What can we do to reduce our MIPS-based software licensing costs from our third party vendors?
Consider using IBM System z Integrated Information Processor
What about 8 Gbps FICON?
IBM has already announced
[FICON Express8] host bus adapter (HBA) cards, that will auto-negotiate to 4Gbps and 2Gbps speeds. If you don't need full 8Gbps speed now, you can
still get the Express8 cards, but put 4/2/1 Gbps SFP ports instead. Currently, LongWave (LW) is only supported to 4km at 8Gbps speed.
I want to use Global Mirror for my DS8100 to my remote DS8100, but also make test copies of my production data to
an older ESS 800 I have locally. Any suggestions? Yes, consider using FlashCopy to simplify this process.
I have Global Mirror (GM) running now successfully with DSCLI, and now want to deploy IBM Tivoli Storage Productivity Center for Replication. Is that possible? Yes, Productivity Center for Replication will detect existing GM relationships, and start managing them.
I have already deployed HyperPAV and zHPF, is there any value in getting Solid-State Drives as well?
HyperPAV and zHPF impact CONN time, but SSD impacts DISC time, so they are mutually complementary.
How should I size my FlashCopy SE pool? SE refers to "Space Efficient", which stores only the changes
between the source and destination copies of each LUN or CKD volume involved. General recommendation is to start with 20 percent and adjust accordingly.
How many RAID ranks should I configure per DS8000 extent pool? IBM recommends 4 to 8 ranks per pool.
Meet the Experts: Storage for Linux, UNIX and Windows distributed systems
This session was focused on storage systems attached to distributed servers, as well as products from Tivoli used to manage them. Here were some of the questions answered:
When we migrated from Tivoli Storage Manager v5 to v6, we lost our favorite "Operational Reporting" tool. How can we get TOR back? You now get the new Tivoli Common Reporting tool.
How can we identify appropriate port distribution for multiple SVC node pairs for load balancing?
IBM Tivoli Storage Productivity Center v4.1 has hot-spot analysis with recommendations for Vdisk migrations.
We tried TotalStorage Productivity Center way back when, but the frequent upgrades were killing us. How has it been lately? It has been much more stable since v3.3, and completely renamed to Tivoli Storage Productivity Center to avoid association with versions 1 and 2 of the predecessor product. The new "lightweight agents" feature of v4.1 resolve many of the problems you were experiencing.
We have over 1600 SVC virtual disks, how do we handle this in IBM Tivoli Storage Productivity Center? Use the Filter capability in combination with clever naming conventions for your virtual disks.
How can we be clever when we are limited to only 15 characters? Ok. We understand.
We are currently using an SSPC with Windows 2003 and 2GB memory, but we are only using the Productivity Center for Replication feature of it. Can we move the DB2 database over to a Windows 2008 server with 4GB of memory?
Consider using the IBM Tivoli Storage Productivity Center for Replication software instead of SSPC for special
circumstances like this.
We love the XIV GUI, how soon will all other IBM storage products have it also? As with every acquisition,
IBM evaluates if there are technologies from new products that can be carried back to existing products.
We are currently using 12 ports on our existing XIV, and love it so much we plan to buy a second frame, but are concerned about consuming another 12 ports on our SAN switch. Any suggestions? Yes, use only six ports per frame. Just because you have more ports, doesn't mean you are required to use them.
We have heard there are concerns from the legal community about using deduplication technology, any ideas how to address that?
Nobody here in the room is a lawyer, and you should consult legal counsel for any particular situation.
None of the IBM offerings intended for non-erasable, non-rewriteable (NENR) data retention records (DR550, WORM tape, N series SnapLock) support dedupe today, and none of IBM's deduplication offerings (TS7650,N series A-SIS,TSM) make any claims for fit-for-purpose for compliance regulatory storage. However, be assured that all of IBM's dedupe technology involves byte-for-byte comparisons so that you never lose any data due to false hash collisions. For all IBM compliance storage, what you write will be read back in the correct sequence of ones and zeros.
Continuing my week in Chicago, for the IBM Storage Symposium 2008, we had sessions that focused on individual products. IBM System Storage SAN Volume Controller (SVC) was a popular topic.
SVC - Everything you wanted to know, but were afraid to ask!
Bill Wiegand, IBM ATS, who has been working with SAN Volume Controller since it was first introduced in 2003. answered some frequently asked questions about IBM System Storage SAN Volume Controller.
Do you have to upgrade all of your HBAs, switches and disk arrays to the recommended firmware levels before upgrading SVC? No. These are recommended levels, but not required. If you do plan to update firmware levels, focus on the host end first, switches next, and disk arrays last.
How do we request special support for stuff not yet listed on the Interop Matrix?
Submit an RPQ/SCORE, same as for any other IBM hardware.
How do we sign up for SVC hints and tips? Go to the IBM
[SVC Support Site] and select the "My Notifications" under the "Stay Informed" box on the right panel.
When we call IBM for SVC support, do we select "Hardware" or "Software"?
While the SVC is a piece of hardware, there are very few mechanical parts involved. Unless there are sparks,
smoke, or front bezel buttons dangling from springs, select "Software". Most of the questions are
related to the software components of SVC.
When we have SVC virtualizing non-IBM disk arrays, who should we call first?
IBM has world-renown service, with some of IT's smartest people working the queues. All of the major storage vendors play nice
as part of the [TSAnet Agreement when a mutual customer is impacted.
When in doubt, call IBM first, and if necessary, IBM will contact other vendors on your behalf to resolve.
What is the difference between livedump and a Full System Dump?
Most problems can be resolved with a livedump. While not complete information, it is generally enough,
and is completely non-disruptive. Other times, the full state of the machine is required, so a Full System Dump
is requested. This involves rebooting one of the two nodes, so virtual disks may temporarily run slower on that
What does "svc_snap -c" do?The "svc_snap" command on the CLI generates a snap file, which includes the cluster error log and trace files from all nodes. The "-c" parameter includes the configuration and virtual-to-physical mapping that can be useful for
disaster recovery and problem determination.
I just sent IBM a check to upgrade my TB-based license on my SVC, how long should I wait for IBM to send me a software license key?
IBM trusts its clients. No software license key will be sent. Once the check clears, you are good to go.
During migration from old disk arrays to new disk arrays, I will temporarily have 79TB more disk under SVC management, do I need to get a temporary TB-based license upgrade during the brief migration period?
Nope. Again, we trust you. However, if you are concerned about this at all, contact IBM and they will print out
a nice "Conformance Letter" in case you need to show your boss.
How should I maintain my Windows-based SVC Master Console or SSPC server?
Treat this like any other Windows-based server in your shop, install Microsoft-recommended Windows updates,
run Anti-virus scans, and so on.
Where can I find useful "How To" information on SVC?
Specify "SAN Volume Controller" in the search field of the
[IBM Redbooks vast library of helpful books.
I just added more managed disks to my managed disk group (MDG), can I get help writing a script to redistribute the extents to improve wide-striping performance?
Yes, IBM has scripting tools available for download on
[AlphaWorks]. For example, svctools will take
the output of the "lsinfo" command, and generate the appropriate SVC CLI to re-migrate the disks around to optimize
performance. Of course, if you prefer, you can use IBM Tivoli Storage Productivity Center instead for a more
Any rules of thumb for sizing SVC deployments?
IBM's Disk Magic tool includes support for SVC deployments. Plan for 250 IOPS/TB for light workloads,
500 IOPS/TB for average workloads, and 750 IOPS/TB for heavy workloads.
Can I migrate virtual disks from one manage disk group (MDG) to another of different extent size?
Yes, the new Vdisk Mirroring capability can be used to do this. Create the mirror for your Vdisk between the
two MDGs, wait for the copy to complete, and then split the mirror.
Can I add or replace SVC nodes non-disruptively? Absolutely, see the Technotes
[SVC Node Replacement page.
Can I really order an SVC EE in Flamingo Pink? Yes. While my blog post that started all
this [Pink It and Shrink It] was initially just some Photoshop humor, the IBM product manager for SVC accepted this color choice as an RPQ option.
The default color remains Raven Black.
Continuing my week in Chicago, for the IBM Storage Symposium 2008, I attended two presentations on XIV.
XIV Storage - Best Practices
Izhar Sharon, IBM Technical Sales Specialist for XIV, presented best practices using XIV in various environments.He started out explaining the innovative XIV architecture: a SATA-based disk system from IBM can outperformFC-based disk systems from other vendors using massive parallelism. He used a sports analogy:
"The men's world record for running 800 meters was set in 1997 by Wilson Kipketer of Denmark in a time of 1:41.11.
However, if you have eight men running, 100 meters each, they will all cross the finish line in about 10 seconds."
Since XIV is already self-tuning, what kind of best practices are left to present? Izhar presented best practicesfor software, hosts, switches and storage virtualization products that attach to the XIV. Here's some quickpoints:
Use as many paths as possible.
IBM does not require you to purchase and install multipathing software as other competitors might. Instead, theXIV relies on multipathing capabilities inherent to each operating system.For multipathing preference, choose Round-Robin, which is now available onAIX and VMware vSphere 4.0, for example. Otherwise, fixed-path is preferred over most-recently-used (MRU).
Encourage parallel I/O requests.
XIV architecture does not subscribe to the outdated notion of a "global cache". Instead, the cache is distributed across the modules, to reduce performance bottlenecks. Each HBA on the XIV can handle about 1400requests. If you have fewer than 1400 hosts attached to the XIV, you can further increase parallel I/O requests by specifying a large queue depth in the host bus adapter (HBA).An HBA queue depth of 64 is a good start. Additional settings mightbe required in the BIOS, operating system or application for multiple threads and processes.
For sequential workloads, select host stripe size less than 1MB. For random, select host stripe size larger than 1MB. Set rr_min_io between ten(10) and the queue depth(typically 64), setting it to half of the queue depth is a good starting point.
If you have long-running batch jobs, consider breaking them up into smaller steps and run in parallel.
Define fewer, larger LUNs
Generally, you no longer need to define many small LUNs, a practice that was often required on traditionaldisk systems. This means that you can now define just 1 or 2 LUNs per application, and greatly simplifymanagement. If your application must have multiple LUNs in order to do multiple threads or concurrent I/O requests, then, by all means, define multiple LUNs.
Modern Data Base Management Systems (DBMS) like DB2 and Oracle already parallelize their I/O requests, sothere is no need for host-based striping across many logical volumes. XIV already stripes the data for you.If you use Oracle Automated Storage Management (ASM), use 8MB to 16MB extent sizes for optimal performance.
For those virtualizing XIV with SAN Volume Controller (SVC), define manage disks as 1632GB LUNs, in multiple of six LUNs per managed disk group (MDG), to balance across the six interface modules. Define SVC extent size to 1GB.
XIV is ideal for VMware. Create big LUNs for your VMFS that you can access via FCP or iSCSI.
Organize data to simplify Snapshots.
You no longer need to separate logs from databases for performance reasons. However, for some backup productslike IBM Tivoli Storage Manager (TSM) for Advanced Copy Services (ACS), you might want to keep them separatefor snapshot reasons. Gernally, putting all data for an application on one big LUNgreatly simplifies administration and snapshot processing, without losing performance.If you define multiple LUNs for an application, simply put them into the same "consistencygroup" so that they are all snapshot together.
OS boot image disks can be snapshot before applying any patches, updates or application software, so that ifthere are any problems, you can reboot to the previous image.
Employ sizing tools to plan for capacity and performance.
The SAP Quicksizer tool can be used for new SAP deployments, employing either the user-based orthroughput-based sizing model approach. The result is in mythical unit called "SAPS", which represents0.4 IOPS for ERP/OLTP workloads, and 0.6 IOPS for BI/BW and OLAP workloads.
If you already have SAP or other applications running, use actual I/O measurements. IBM Business Partners and field technical sales specialists have an updated version of Disk Magic that can help size XIV configurations fromPERFMON and iostat figures.
Lee La Frese, IBM STSM for Enteprise Storage Performance Engineering, presented internal lab test results forthe XIV under various workloads, based on the latest hardware/software levels [announced two weeks ago]. Three workloadswere tested:
Web 2.0 (80/20/40) - 80 percent READ, 20 percent WRITE, 40 percent cache hits for READ.YouTube, FlickR, and the growing list at [GoWeb20] are applications with heavy read activity, but because of[long-tail effects], may not be as cache friendly.
Social Networking (50/50/50) - 50 percent READ, 50 percent WRITE, 50 percent cache hits for READ.Lotus Connections, Microsoft Sharepoint, and many other [social networking] usage are more write intensive.
Database (70/30/50) - 70 percent READ, 30 percent WRITE, 50 percent cache hits for READ.The traditional workload characteristics for most business applications, especially databases like DB2 andOracle on Linux, UNIX and Windows servers.
The results were quite impressive. There was more than enough performance for tier 2 application workloads,and most tier 1 applications. The performance was nearly linear from the smallest 6-module to the largest 15-module configuration. Some key points:
A full 15-module XIV overwhelms a single SVC 8F4 node-pair. For a full XIV, consider 4 to 8 nodes 8F4 models, or 2 to 4 nodes of an 8G4. For read-intensive cache-friendly workloads, an SVC in front of XIV was able to deliver over 300,000 IOPS.
A single node TS7650G ProtecTIER can handle 6 to 9 XIV modules. Two nodes of TS7650G were needed to drivea full 15-module XIV. A single node TS7650 in front of XIV was able to ingest 680 MB/sec on the seventh day with17 percent per-day change rate test workload using 64 virtual drives. Reading the data back got over 950 MB/sec.
For SAP environments where response time 20-30 msec are acceptable, the 15-module XIV delivered over 60,000 IOPS. Reducing this down to 25,000-30,000 cut the msec response time to a faster 10-15 msec.
These were all done as internal lab tests. Your mileage may vary.
Not surprisingly, XIV was quite the popular topic here this week at the Storage Symposium. There were many moresessions, but these were the only two that I attended.
Continuing my week in Chicago for the IBM Storage and Storage Networking Symposium and System x and BladeCenter Technical Conference, I presented a variety of topics.
Hybrid Storage for a Green Data Center
The cost of power and cooling has risen to be a #1 concern among data centers. I presented the following hybrid storage solutions that combine disk with tape. These provide the best of both worlds, the high performance access time of disk with the lower costs and reduced energy consumption of tape.
IBM [System Storage DR550] - IBM's Non-erasable, Non-rewriteable (NENR) storage for archive and compliance data retention
IBM Grid Medical Archive Solution [GMAS] - IBM's multi-site grid storage for PACS applications and electronic medical records[EMR]
IBM Scale-out File Services [SoFS] - IBM's scalable NAS solution that combines a global name space with a clustered GPFS file system, serving as the ideal basis for IBM's own[Cloud Computing and Storage] offerings
Not only do these help reduce energy costs, they provide an overall lower total cost of ownership (TCO) thantraditional WORM optical or disk-only storage configurations.
The Convergence of Networks - Understanding SAN, NAS and iSCSI in the Data Center Network
This turned out to be my most popular session. Many companies are at a crossroads in choosing data and storage networking solutions in light of recent announcements from IBM and others. In the span of 75 minutes, I covered:
Block storage concepts, storage virtualization and RAID levels
File system concepts, how file systems map files to block storage
Network Attach Storage, the history of the NFS and CIFS protocols, Pros and Cons of using NAS
Storage Area Networks, the history of SAN protocols including ESCON, FICON and FCP, Pros and Cons of using SAN
IP SAN technologies, iSCSI and Fibre Channel over Ethernet (FCoE), Pros and Cons of using this approach
Network Convergence with Infiniband and Fibre Channel over Convergence Enhanced Ethernet (FCoCEE), why Infiniband was not adopted historically in the marketplace as a storage protocol, and the features and enhancements of Convergence Enhanced Ethernet (CEE) needed to merge NAS, SAN and iSCSI traffic onto a single converged data center network [DCN]
Yes, it was a lot of information to cover, but I managed to get it done on time.
IBM Tivoli Storage Productivity Center version 4.1 Overview and Update
In conferences like these, there are two types of product-level presentations. An "Overview" explains howproducts work today to those who are not familiar with it. An "Update" explains what's new in this version of the product for those who are already familiar with previous releases. I decided to combine these into one sessionfor IBM's new version of [Tivoli Storage Productivity Center].I was one of the original lead architects of this product many years ago, and was able to share many personalexperiences about its evolution in development and in the field at client facilities.Analysts have repeatedly rated IBM Productivity Center as one of the top Storage Resource Management (SRM) tools available in the marketplace.
Information Lifecycle Management (ILM) Overview
Can you believe I have been doing ILM since 1986? I was the lead architect for DFSMS which provides ILM support for z/OS mainframes. In 2003-2005, I spent 18 months in the field performingILM assessments for clients, and now there are dozens of IBM practitioners in Global Technology Services andSTG Lab Services that do this full time. This is a topic I cover frequently at the IBM Executive Briefing Center[EBC], because it addressesseveral top business challenges:
Reducing costs and simplifying management
Improving efficiency of personnel and application workloads
Managing risks and regulatory compliance
IBM has a solution based on five "entry points". The advantage of this approach is that it allows our consultants to craft the right solution to meet the specific requirements of each client situation. These entry points are:
Tiered Information Infrastructure - we don't limit ourselves to just "Tiered Storage" as storage is only part of a complete[information infrastructure] of servers,networks and storage
Storage Optimization and Virtualization - including virtual disk, virtual tape and virtual file solutions
Process Enhancement and Automation - an important part of ILM are the policies and procedures, such as IT Infrastructure Library [ITIL] best practices
Archive and Retention - space management and data retention solutions for email, database and file systems
I did not get as many attendees as I had hoped for this last one, as I was competing head-to-head in the same time slot as Lee La Frese covering IBM's DS8000 performance with Solid State Disk (SSD) drives, John Sing covering Cloud Computing and Storage with SoFS, and Eric Kern covering IBM Cloudburst.
I am glad that I was able to make all of my presentations at the beginning of the week, so that I can then sit back and enjoy the rest of the sessions as a pure attendee.
In general, people agree that IBM, HP and EMC are the top three vendors in storage,with HDS, Sun and Dell rounding out the top six.
The fun begins when a respected analyst like IDC Corp. publishes their calculations,and individual vendors re-swizzle the results because they are not happy with theirfindings.
I thought it would be helpful to illustrate how this all works. First, you need to comeup with a defintion of what you are going to count. You could count units sold, revenue dollars, or capacity Terabytes, or some other generally accepted metric.
Next, you need to define what's in and what's out. For example, you can say "storage"which would include both disk drives and tape drives, both internal to servers, orexternal to servers, or you can choose a more narrow definition, say external disksystems, which might suit you better if you aren't in the tape business, and don't sell servers.
By some definitions, my Apple iPod, Motorolla cell phone, and Canon digital camera,could all be counted as external disk systems, as they all connect via USB cableto my IBM laptop, and act like a disk drive to my Windows operating system, allowingme to read and write data back and forth. It is necessary to define exactly what you plan to include,and what to exclude, based on the reported numbers available.
The last rule is that nothing gets double-counted. In our complicated industry ofmanufacturers and vendors, sometimes storage is manufactured by one company, but soldby another, typically under the vendor's brand, not the manufacturer's brand. Youcan either count manufactured units, or vendor units, but you can't mix and match.
IBM is both manufacturer and vendor. However, IDC only counts vendor units, so storagemanufactured by someone else, but sold by IBM is counted as IBM, and storage manufacturedby IBM but branded by someone else goes to that other vendor. Likewise, HP and Sun re-brandHitachi storage, and Dell re-brands EMC storage.
EMC would like to treat all EMC-manufactured storage re-branded by Dell as EMC vended storage,so that it can move up in the ratings. But Dell wants to count it too, so that it can appearin the top six. You can't have it both ways.
But are these ratings just "bragging rights"? Not always. When big purchases are planned fornew projects, or a client decides its time to throw out the current vendor and shop for a newone, the ratings could influence that decision. In that regard, IDC 4Q05 Storage Tracker reportedIBM as number one over all in storage hardware at the end of 2005, which includes both internal and external disk systems, as well as tape drives sold under the IBM brand, based on dollar revenues. By this method of counting, HP came in at number 2, EMC at number 3, and the rest round out thetop six as before.
In the end, this is just one factor when deciding which brand to choose for your storage needs.
Rich Bourdeau has written a nice article on InfoStor titled [Software as a Service (SaaS) meets Storage]. Last year, IBM acquired Arsenal Digital, and he mentions both in this article.It is interesting how this has evolved over the years.
Rent warehouse space for tapes
I remember when various companies offered remote storage for tapes. These would be temperature and humidity-controlledrooms, with access lists on who could bring tapes in, who could take tapes out, and so on. In the event of thedisaster, someone would collect the appropriate tapes and take them to a recovery site location.
Rent online/nearline storage from a Storage Service Provider (SSP)
SSPs rented storage space on disk, or provided automated tape libraries that could be written to. With tapes being ejected and stored in temperature/humidity-controlled vaults. Electronic vaulting eliminates a lot of theissues with cartridge handling and transportation, is more secure, and faster. Rented disk space, based on a Gigabytes-per-month rate, could be used for whatever the customer wanted. If these were for backups or archive,then the customer has to have their own software, to do their own processing at their own location, sending the data to the remote storage as appropriate, and manage their own administration.
Backup-as-a-Service and Archive-as-a-Service
We are now seeing the SaaS model applied to mundane and routine storage management tasks. New providers can offerthe software to send backups, the disk to write them to, and as needed the tape libraries and cartridges to rollover when the disk space is full. Disk capacity can be sized so that the most recent backups are on immediately accessible for fast recovery.
The same concept can be applied to archives. The key difference between a backup and an archive is that backups areversion-based. You might keep three versions of a backup, the most recent, and two older copies, in case something is wrong with the most recent copy, you can go back to older copies. This could be from undetected corruption of the data itself, or problems with the disk or tape media. An archive, on the other hand, is time-based. You want this data to be kept for a specific period of time, based on an event or fixed period of years.
Since BaaS and AaaS providers know what the data is, have some idea of the policies and usage patterns will be, can then optimize a storage solution that best meets service level agreements.
Continuing this week in Los Angeles, I went to some interesting sessions today at theSystems Technical Conference (STC08).
System Storage Productivity Center (SSPC) - Install and Configuration
Dominic Pruitt, an IBM IT specialist in our Advanced Technical Support team, presented SSPC and howto install and configure it. For those confused between the difference of TotalStorage ProductivityCenter and System Storage Productivity Center, the former is pure software that you install on aWindows or Linux server, and the latter is an IBM server, pre-installed with Windows 2003, TotalStorageProductivity Center software, TPCTOOL command line interface, DB2 Universal Database, the DS8000 Element Manager, SVC GUI and CIMOM, and [PuTTY] rLogin/SSH/Telnet terminal application software.
Of course, the problem with having a server pre-installed with a lot of software is that there is alwayssomeone that wants to customize it further. For those who just want to manage their DS8000 disk systems,for example, it is possible to uninstall the SVC GUI, CIMOM and PuTTY, and re-install them later when youchange your mind. As a general rule, it is not wise to mix CIMOMs on the same machine, as it might causeconflicts with TCP ports or Java level requirements, so if you want a different CIMOM than SVC, uninstallthe SVC CIMOM first. For those who have SVC, the SSPC replaces the SVC Master Console, so you can safelyturn off the SVC CIMOM on your existing SVC Master Consoles.
The base level is TotalStorage Productivity Center "Basic Edition", but you can upgrade the Productivity Centerfor Disk, Data and Fabric components with license keys. You can also run Productivity Center for Replication,but IBM recommends adding processor and memory to do this (IBM offers this as an orderable option).Whether you have the TotalStorage software or SSPC hardware, Productivity Center has a cool role-to-groups mapping feature.You can create user groups, either on the Windows server, the Active Directory, or other LDAP, and then map which roles should be assigned to users in each group.
Since Productivity Center manages a variety of different disk systems, it has made anattempt to standardize some terminology. The term "storage pool" refers to an extentpool on the DS8000, or a managed disk group on the SAN Volume Controller. Since the DS8000 can support both mainframe CKD volumes and LUNs for distributed systems, theterm "volume" refers to a CKD volume or LUN, and "disk" refers to the hard disk drive (HDD).
To help people learn Productivity Center, IBM offers single-day "remote workshops"that use Windows Remote Desktop to allow participants to install, customize and usethe software with no travel required.
IBM Integrated Approach to Archiving
Dan Marshall, IBM global program manager for storage and data services on our Global Technology Services team, presented IBM's corporate-wide integration to support archive across systems, software and services.One attendee asked me why I was there, given that "archive" is one of my areas of subject matter expertise that I present often at the Tucson Executive Briefing Center. I find it useful to watch others present the material, even material that I helped to develop, to see a different slant or spin on each talking point.
Archive is one area that brings all parts of IBM together: systems, software and services.Dan provided a look at archive from the services angle, providing an objective unbiasedview of the different software and systems available to solve specific challenges.
Encryption Key Manager (EKM) Design and Implementation
Jeff Ziehm, IBM tape technical sales specialist, presented IBM's EKM software, how it works in a tape environment, and how to deploy it in various environments. Since IBM is allabout being open and non-proprietary, the EKM software runs on Java on a variety ofIBM and non-IBM operating systems. IBM offers "keytool" command line interface (CLI) for the LTO4 and TS1120 tape systems, and "iKeyMan" graphical user interface (GUI) for theTS1120. Since it runs on Java, IBM Business Partners and technical support personneloften just [download and install EKM]onto their own laptops to learn how to use it.
Virtual Tape Update
We had three presenters at this one. First, Jeff Mulliken, formerly from Diligent and now a full IBM employee, presented the current ProtecTier softwarewith the HyperFactor technology, then Abbe Woodcock, IBM tape systems, compared Diligent with IBM's TS7520 and just-announced TS7530virtual tape libraries, and finally Randy Fleenor, IBM tape sales leader, presented IBM's strategy going forward in tape virtualization.
Let's start with Diligent. The ProtecTier software runs on any x86-64 server withat least four cores and the correct Emulex host bus adapter (HBA) cards. Using Red HatEnterprise Linux (RHEL) as a base, the ProtecTier software performs its deduplication entirely in-lineat an "ingest rate" of 400-450 MB/sec. This is all possible using 4GB memory-resident "dictionary table" that can map up to 1 PB of back end physical storage, which could represent as much as 25PB of "nominal" storage. Theserver is then point-to-point or SAN-attached to Fibre Channel disk systems.
As we learned yesterday from Toby Marek's session, there are four ways to performdeduplication:
full-file comparisons. Store only one copy of identical files.
fixed-chunk comparisons. Files are carved up into fixed-size chunks, and each chunkis compared or hashed to existing chunks to eliminate duplicates.
variable-chunk comparisons. Variable-length chunks are hashed or diffed to eliminate duplicate data.
content-aware comparisons. If you knew data was in Powerpoint format, for example,you could compare text, photos or charts against other existing Powerpoint files toeliminate duplicates.
IBM System Storage N series Advanced Single Instance Storage (A-SIS) uses fixed-chunkmethod, and Diligent uses variable-chunk comparisons. Diligent does this using "dataprofiling". For example, let's say most of my photographs are pictures of people, buildings, landscapes, flowers and IT equipment. When I back these up, the Diligentserver "profiles" each, and determines if any existing data have a similar profilethat might have at least 50 percent similar content. Diligent than reads in the data that is mostly likely similar, does a byte-for-byte ["diff" comparison], and creates variable-lengthchunks that are either identical or unique to sections of the existing data. Theunique data is compressed with LZH and written to disk, and the sequential series of pointer segments representing the ingested file is written in a separate section on disk.
That Diligent can represent profiles for 1PB of data in as little as 4GB memory-residentdictionary is incredible. By comparison, 10TB data would require 10 million entries on a content-aware solution, and 1.25 billion entries for one based on hash-codes.
Abbe Woodcock presented the TS7530 tape system that IBM announced on Tuesday. It has some advantages over the current Diligent offering:
Hardware-based compression (TS7520 and Diligent use software-based compression)
1200 MB/sec (faster ingest rate than Diligent)
1.7PB of SATA disk (more disk capacity than Diligent)
Support for i5/OS (Diligent's emulation of ATL P3000 with DLT7000 tapes not supported on IBM's POWER systems running i5/OS)
Ability to attach a real tape library
NDMP backup to tape
tape "shredding" (virtual equivalent of degaussing a physical tape to erase all previously stored data)
Randy Fleenor wrapped up the session telling us IBM's strategy going forward with all of thevirtual tape systems technologies. Until then, IBM is working on "recipes" or "bundles", puttingDiligent software with specific models of IBM System x servers and IBM System Storage DS4000 disk systemsto avoid the "do-it-yourself" problems of its current software-only packaging.
Understanding Web 2.0 and Digital Archive Workloads
I got to present this in the last time slot of the day, just before everyone headed off to the [Westin Bonaventure hotel] for our big fancy barbecue dinner. Like my previous sessionon IBM Strategy, this session was more oriented toward a sales audience, but both garnereda huge turn-out and were well-received by the technical attendees.
This session was requested because these new applications and workloads are what is driving IBM to acquire small start-ups like XIV, deploy Scale-Out File Services (SOFS), and develop the innovative iDataPlex server rack.
The session was fun because it was a mix of explanation of the characteristics ofWeb 2.0 services; my own experience as a blogger and user of Google Docs, FlickR, Second Life andTivo; and an exploration in how database and digital archives will impact thegrowth in computing and storage requirements.
I'll expand on some of these topics in later blog posts.
My session was the first in the morning, at 8:30am, but managed to pack the room full of people. A few looklike they just rolled in from Brocade's special get-together in Casey's Irish Pub the night before.I presented how IBM's storage strategy for the information infrastructure fits into the greater corporate-wide themes.To liven things up, I gave out copies of my book[Inside System Storage: Volume I] to those who asked or answered the toughest questions.
Data Deduplication and IBM Tivoli Storage Manager (TSM)
IBM Toby Marek compared and contrasted the various data deduplication technologies and products available, andhow to deploy them as the repository for TSM workloads. She is a software engineer for our TSM software product,and gave a fair comparison between IBM System Storage N series Advanced Single Instance Storage (A-SIS), IBMDiligent, and other solutions out in the marketplace.If you are going to combine technologies, then it isbest to dedupe first, then compress, and finally encrypt the data. She also explained about the many cleverways that TSM does data reduction at the client side greatly reduces the bandwidth traffic over the LAN,as well as reducing disk and tape resources for storage. This includes progressive "incremental forever" backup for file selection, incremental backups for databases, and adaptive sub-file backup.Because of these data reduction techniques, you may not get as much benefit as deduplication vendors claim.
The Business Value of Energy Efficiency Data Centers
Scott Barielle did a great job presenting the issues related to the Green IT data center. He is part of IBM"STG Lab Services" team that does energy efficiency studies for customers. It is not unusual for his teamto find potential savings of up to 80 percent of the Watts consumed in a client's data center.
IBM has done a lot to make its products more energy efficient. For example, in the United States, most datacenters are supplied three-phase 480V AC current, but this is often stepped down to 208V or 110V with powerdistribution units (PDUs). IBM's equipment allows for direct connection to this 480V, eliminating the step-downloss. This is available for the IBM System z mainframe, the IBM System Storage DS8000disk system, and larger full-frame models of our POWER-based servers, and will probably be rolled out to someof our other offerings later this year. The end result saves 8 to 14 percent in energy costs.
Scott had some interesting statistics. Typical US data centers only spend about 9 percent of their IT budgeton power and cooling costs. The majority of clients that engage IBM for an energy efficiency study are not tryingto reduce their operational expenditures (OPEX), but have run out, or close to running out, of total kW ratingof their current facility, and have been turned down by their upper management to spend the average $20 million USDneeded to build a new one. The cost of electricity in the USA has risen very slowly over the past 35 years, andis more tied the to fluctuations of Natural Gas than it is to Oil prices.(a recent article in the Dallas News confirmed this:["As electricity rates go up, natural gas' high prices, deregulation blamed"])
Cognos v8 - Delivering Operational Business Intelligence (BI) on Mainframe
Mike Biere, author of the book [BusinessIntelligence for the Enterprise], presented Cognos v8 and how it is being deployed for the IBMSystem z mainframe. Typically, customers do their BI processing on distributed systems, but 70 percent of the world's business data is on mainframes, so it makes sense to do yourBI there as well. Cognos v8 runs on Linux for System z, connecting to z/OS via [Hypersockets].
There are a variety of other BI applications on the mainframe already, including DataQuant,AlphaBlox, IBI WebFocus and SAS Enterprise Business Intelligence. In addition to accessing traditional onlinetransaction processing (OLTP) repositories like DB2, IMS and VSAM, using the [IBM WebSphere ClassicFederation Server], Cognos v8 can also read Lotus databases.
Business Intelligence is traditionally query, reporting and online analytics process (OLAP) for the top 10 to 15 percent of the company, mostly executives andanalysts, for activities like business planning, budgeting and forecasting. Cognos PowerPlay stores numericaldata in an [OLAP cube] for faster processing.OLAP cubes are typically constructed with a batch cycle, using either "Extract, Transfer, Load" [ETL], or "Change Data Capture" [CDC], which playsto the strength of IBM System z mainframe batch processing capabilities.If you are not familiar with OLAP, Nigel Pendse has an article[What is OLAP?] for background information.
Over the past five years, BI is now being more andmore deployed for the rest of the company, knowledge workers tasked with doing day-to-day operations. Thisphenomenom is being called "Operational" Business Intelligence.
IBM Glen Corneau, who is on the Advanced Technical Support team for AIX and System p, presented the IBMGeneral Parellel File System (GPFS), which is available for AIX, Linux-x86 and Linux on POWER.Unfortunately, many of the questions were related to Scale Out File Services (SOFS), which my colleague GlennHechler was presenting in another room during this same time slot.
GPFS is now in its 11th release since its introducing in 1997. All of the IBM supercomputers on the [Top 500 list] use GPFS. The largest deployment of GPFS is 2241 nodes.A GPFS environment can support up to 256 file systems, each file system can have up to 2 billion filesacross 2 PB of storage. GPFS supports "Direct I/O" making it a great candidate for Oracle RAC deployments.Oracle 10g automatically detects if it is using GPFS, and sets the appropriate DIO bits in the stream totake advantage of GPFS features.
Glen also covered the many new features of GPFS, such as the ability to place data on different tiers ofstorage, with policies to move to lower tiers of storage, or delete after a certain time period, all conceptswe call Information Lifecycle Management. GPFS also supports access across multiple locations and offersa variety of choices for disaster recovery (DR) data replication.
Perhaps the only problem with conferences like this is that it can be an overwhelming["fire hose"] of information!
On his The Storage Architect blog, Chris Evans wrote [Twofor the Price of One]. He asks: why use RAID-1 compared to say a 14+2 RAID-6 configuration which would be much cheaper in terms of the disk cost? Perhpaps without realizing it, answers itwith his post today [XIV part II]:
So, as a drive fails, all drives could be copying to all drives in an attempt to ensure the recreated lost mirrors are well distributed across the subsystem. If this is true, all drives would become busy for read/writes for the rebuild time, rather than rebuild overhead being isolated to just one RAID group.
Let me try to explain. (Note: This is an oversimplification of the actual algorithm in an effortto make it more accessible to most readers, based on written materials I have been provided as partof the acquisition.)
In a typical RAID environment, say 7+P RAID-5, you might have to read 7 drives to rebuild one drive, and in the case of a 14+2 RAID-6, reading 15 drives to rebuild one drive. It turns out the performance bottleneck is the one driveto write, and today's systems can rebuild faster Fibre Channel (FC) drives at about 50-55 MB/sec, and slower ATA disk at around 40-42 MB/sec. At these rates, a 750GB SATA rebuild would take at least 5 hours.
In the IBM XIV Nextra architecture, let's say we have 100 drives. We lose drive 13, and we need to re-replicate any at-risk 1MB objects.An object is at-risk if it is the last and only remaining copy on the system. A 750GB that is 90 percent full wouldhave 700,000 or so at-risk object re-replications to manage. These can be sorted by drive. Drive 1 might have about 7000 objects that need re-replication, drive 2might have slightly more, slightly less, and so on, up to drive 100. The re-replication of objects on these other 99 drives goes through three waves.
Select 49 drives as "source volumes", and pair each randomly with a "destination volume". For example, drive 1 mapped todrive 87, drive 2 to drive 59, and so on. Initiate 49 tasks in parallel, each will re-replicate the blocks thatneed to be copied from the source volume to the destination volume.
50 volumes left.Select another 49 drives as "source volumes", and pair each with a "destination volume". For example, drive 87 mapped todrive 15, drive 59 to drive 42, and so on. Initiate 49 tasks in parallel, each will re-replicate the blocks thatneed to be copied from the source volume to the destination volume.
Only one drive left. We select the last volume as the source volume, pair it off with a random destination volume,and complete the process.
Each wave can take as little as 3-5 minutes. The actual algorithm is more complicated than this, as tasks complete early the source and volumes drives are available for re-assignment to another task, but you get the idea. XIV hasdemonstrated the entire process, identifying all at-risk objects, sorting them by drive location, randomly selectingdrive pairs, and then performing most of these tasks in parallel, can be done in 15-20 minutes. Over 40 customershave been using this architecture over the past 2 years, and by now all have probably experienced at least adrive failure to validate this methodology.
In the unlikely event that a second drive fails during this short time, only one of the 99 task fails. The other 98 tasks continue to helpprotect the data. By comparison, in a RAID-5 rebuild, no data is protected until all the blocks are copied.
As for requiring spare capacity on each drive to handle this case, the best disks in production environments aretypically only 85-90 percent full, leaving plenty of spare capacity to handle re-replication process. On average,Linux, UNIX and Windows systems tend to only fill disks 30 to 50 percent full, so the fear there is not enough sparecapacity should not be an issue.
The difference in cost between RAID-1 and RAID-5 becomes minimal as hardware gets cheaper and cheaper. For every $1 dollar you spend on storage hardware, you spend $5-$8 dollars managing the environment. As hardware gets cheaper still, it might even be worth making three copies of every 1MB object, the parallel processto perform re-replications would be the same. This could be done using policy-based management, some data gets triple-copied, and other data gets only double-copied, based on whether the user selected "premium" or "basic" service.
The beauty of this approach is that it works with 100 drives, 1000 drives, or even a million drives. Parallel processingis how supercomputers are able to perform feats of amazing mathematical computations so quickly, and how Web 2.0services like Google and Yahoo can perform web searches so quickly. Spreading the re-replication process acrossmany drives in parallel, rather than performing them serially onto a single drive, is just one of the many uniquefeatures of this new architecture.
Wrapping up my week's theme of "diversity", with posts on a diverse set of topics,today I will suggest ways to spendyour time while you are walking 10,000 steps per day, as recommended by the authorsof the book "You: On a Diet".
(If you thought this was about the 10,000 steps it might take to implement a storage solution, you should switch over to IBM as your storage vendor. For example, the DS3200 and DS3400 can beimplemented in as little as SIX steps. That's pretty cool.)
Blogs like Lifehacker are an excellent resource for neat littletips and tricks to help you throughout your day, like how to use your iPod, cell phone or computer better, for example. These suggestions are based on the idea that you can walk your 10,000 steps with access to an iPod and cell phone.
Learning a language
... or refreshing yourself on a language you might not have spoken in a while. In addition to formal audio-based lessons from Pimsleur, there are podcasts you can get for various languages. In preparation for my upcoming trip to Japan and China, I have been listening to JapanesePod101.com and ChinesePod.com which have quick lessons that complement the formal training.This Lifehacker postindicates there are similar ones for French, Spanish, Italian, and Brazillian Portuguese.
Practicing your presentation
Walking while practicing your 30-60 minute presentation would be good exercise.MicroPersuasion explains how to turn your iPod into the ultimate PowerPoint accessory, and this article in PlayListmag.com providesthe steps to get a PowerPoint presentation onto your iPod. I did this, and the slides are found underPhotos->Photo Library. The images are small, but heck, they are your charts and you should recognize themwell enough to remind yourself what to say on each slide.Also, I am able to record my practice sessions using MP3 Recorder and listen as I page through each slide. (In theory, you can use your iPod to present your slides to your audience, plugging the iPod directly into the laptop projector, instead of a laptop, using cables available at your local Apple store, and use the iPod controls as your forward/backward remote.)
Working your To-Do list
You can download your to-do list to your iPod. I use BackPackIt from 37 Signals. You can sign up for a free account, or upgrade to a paid account, and have anamazingly simple browser-based tool to develop your to-do lists, one for each project or aspect of your life. Oncedone, the list can be emailed to you as plain text. Enable your iPod as an "external disk drive" and copy this text file to your NOTES directory on the iPod drive. Voila! You can now read your to-do list! (I could also send it to my cell phone, using firstname.lastname@example.org, but I find the iPod easier to read and navigate)
Think of something to add? Send an email from your cell phone. With BackPackit, I can send an email that will directly add my text as a note or todo list item. On my phone, this is simply sending a text message to "500" with text like:
"email@example.com todo # buy bread".
The hash mark (#) separates the subject line from the body of the email, and this is how Backpackit knows its a todo item or a note. If you pre-program the huge email address in advance on your phone, then it isn't as bad as it looks. It will be on your packpackit page the next time you log in.
Well, that's three suggestions. The next time you complain that there is no time to walk, you now have no excuse.
Wrapping up this week's exploration on disk system performance, today I willcover the Storage Performance Council (SPC) benchmarks, and why I feel they are relevant to help customers make purchase decisions. This all started to address a comment from EMC blogger Chuck Hollis, who expressed his disappointment in IBM as follows:
You've made representations that SPC testing is somehow relevant to customers' environments, but offered nothing more than platitudes in support of that statement.
Apparently, while everyone else in the blogosphere merely states their opinions and moves on,IBM is held to a higher standard. Fair enough, we're used to that.Let's recap what we covered so far this week:
Monday, I explained how seemingly simple questions like "Which is the tallestbuilding?" or "Which is the fastest disk system?" can be steeped in controversy.
Tuesday, I explored what constitutes a disk system. While there are special storage systemsthat include HDD that offer tape-emulation, file-oriented access, or non-erasable non-rewriteable protection,it is difficult to get apples-to-apples comparisions with storage systems that don't offer these special features.I focused on the majority of general-purpose disk systems, those that are block-oriented, direct-access.
Today, I will explore ways to apply these metrics to measure and compare storageperformance.
Let's take, for example, an IBM System Storage DS8000 disk system. This has a controller thatsupports various RAID configurations, cache memory, and HDD inside one or more frames.Engineers who are testing individual components of this system might run specifictypes of I/O requests to test out the performance or validate certain processing.
100% read-hit, this means that all the I/O requests are to read data expectedto be in the cache.
100% read-miss, this means that all the I/O requests are to read data expectedNOT to be in the cache, and must go fetch the data from HDD.
100% write-hit, this means that all the I/O requests are to write data into cache.
100% write-miss, this means that all the I/O requests are to bypass the cache,and are immediately de-staged to HDD. Depending on the RAID configuration, this can result in actually reading or writing several blocks of data on HDD to satisfy thisI/O request.
Known affectionately in the industry as the "four corners" test, because you can show them on a box, with writes on the left, reads on the right,hits on the top, and misses on the bottom.Engineers are proud of these results, but these workloads do notreflect any practical production workload. At best, since all I/O requests are oneof these four types, the four corners provide an expectation range from the worst performance (most often write-missin the lower left corner)and the best performance (most often read-hit in the upper right corner) you might get with a real workload.
To understand what is needed to design a test that is more reflective of real business conditions,let's go back to yesterday's discussion of fuel economy of vehicles, with mileage measured in miles per gallon.The How Stuff Works websiteoffers the following description for the two measurements taken by the EPA:
The "city" program is designed to replicate an urban rush-hour driving experience in which the vehicle is started with the engine cold and is driven in stop-and-go traffic with frequent idling. The car or truck is driven for 11 miles and makes 23 stops over the course of 31 minutes, with an average speed of 20 mph and a top speed of 56 mph.
The "highway" program, on the other hand, is created to emulate rural and interstate freeway driving with a warmed-up engine, making no stops (both of which ensure maximum fuel economy). The vehicle is driven for 10 miles over a period of 12.5 minutes with an average speed of 48 mph and a top speed of 60 mph.
Why two different measurements? Not everyone drives in a city in stop-and-go traffic. Having only one measurement may not reflect the reality that you may travel long distances on the highway. Offering both city and highway measurements allows the consumers to decide which metric relates closer to their actual usage.
Should you expect your actual mileage to be the exact same as the standardized test?Of course not. Nobody drives exactly 11 miles in the city every morning with 23 stops along the way,or 10 miles on the highway at the exact speeds listed.The EPA's famous phrase "your mileage may vary" has been quickly adopted into popular culture's lexicon. All kinds of factors, like weather, distance, anddriving style can cause people to get better or worse mileage than thestandardized tests would estimate.
Want more accurate results that reflect your driving pattern, in specific conditions that you are most likely to drive in? You could rentdifferent vehicles for a week and drive them around yourself, keeping track of whereyou go, and how fast you drove, and how many gallons of gas you purchased, so thatyou can then repeat the process with another rental, and so on, and then use yourown findings to base your comparisons. Perhaps you find that your results are always20% worse than EPA estimates when you drive in the city, and 10% worse when you driveon the highway. Perhaps you have many mountains and hills where you drive, you drive too fast, you run the Air Conditioner too cold, or whatever.
If you did this with five or more vehicles, and ranked them best to worstfrom your own findings, and also ranked them best to worst based on the standardizedresults from the EPA, you likely will find the order to be the same. The vehiclewith the best standardized result will likely also have the best result from your ownexperience with the rental cars. The vehicle with the worst standardized result willlikely match the worst result from your rental cars.
(This will be one of my main points, that standardized estimates don't have to be accurate to beuseful in making comparisons. The comparisons and decisions you would make with estimatesare the same as you would have made with actual results, or customized estimates based on current workloads. Because the rankings are in the same order, they are relevant and useful for making decisions based on those comparisons.)
Most people shopping around for a new vehicle do not have the time or patience to do this with rental cars. Theycan use the EPA-certified standardized results to make a "ball-park" estimate on how much they will spendin gasoline per year, decide only on cars that might go a certain distancebetween two cities on a single tank of gas, or merely to provide ranking of thevehicles being considered. While mileage may not be the only metric used in making a purchase decision, it can certainly be used to help reduce your consideration setand factor in with other attributes, like number of cup-holders, or leather seats.
In this regard, the Storage Performance Council has developed two benchmarks that attempt to reflect normal business usage, similar to "City" and "Highway" driving measurements.
SPC-1 consists of a single workload designed to demonstrate the performance of a storage subsystem while performing the typical functions of business critical applications. Those applications are characterized by predominately random I/O operations and require both queries as well as update operations. Examples of those types of applications include OLTP, database operations, and mail server implementations.
SPC-2 consists of three distinct workloads designed to demonstrate the performance of a storage subsystem during the execution of business critical applications that require the large-scale, sequential movement of data. Those applications are characterized predominately by large I/Os organized into one or more concurrent sequential patterns. A description of each of the three SPC-2 workloads is listed below as well as examples of applications characterized by each workload.
Large File Processing: Applications in a wide range of fields, which require simple sequential process of one or more large files such as scientific computing and large-scale financial processing.
Large Database Queries: Applications that involve scans or joins of large relational tables, such as those performed for data mining or business intelligence.
Video on Demand: Applications that provide individualized video entertainment to a community of subscribers by drawing from a digital film library.
The SPC-2 benchmark was added when people suggested that not everyone runs OLTP anddatabase transactional update workloads, just as the "Highway" measurement was addedto address the fact that not everyone drives in the City.
If you are one of the customers out there willing to spend the time and resources to do your own performance benchmarking, either at your own data center, or with theassistance of a storage provider, I suspect most, if not all, the major vendors(including IBM, EMC and others), and perhaps even some of the smaller start-ups, would be glad to work with you.
If you want to gather performance data of your actual workloads, and use this to estimate how your performance might be with a new or different storage configuration, IBMhas tools to make these estimates, and I suspect (again) that most, if not all, of theother storage vendors have developed similar tools.
For the rest of you who are just looking to decide which storage vendors to invite on your next RFP, and which products you might like to investigate that matchthe level of performance you need for your next project or application deployment,than the SPC benchmarks might help you with this decision. If performance is importantto you, factor these benchmark comparisons with the rest of the attributes you arelooking for in a storage vendor and a storage system.
In my opinion, I feel that for some people, the SPC benchmarks provide some value in this decision making process. They are proportionally correct, in that even ifyour workload gets only a portion of the SPC estimate, that storage systems withfaster benchmarks will provide you better performance than storage systems with lower benchmark results. That is why I feel they can be relevant in makingvalid comparisons for purchase decisions.
Hopefully, I have provided enough "food for thought"on this subject to support why IBM participates in the Storage Performance Council, why the performance of the SAN Volume Controller can be compared to the performanceof other disk systems, and why we at IBM are proud of the recent benchmark results in our recent press release.
My post last week [Solid State Disk on DS8000 Disk Systems] kicked up some dust in the comment section.Fellow blogger BarryB (a member of the elite [Anti-Social Media gang from EMC]) tried to imply that 200GB solid state disk (SSD) drives were different or better than the 146GB drives used in IBM System Storage DS8000 disk systems. I pointed out that they are the actual same physical drive, just formatted differently.
To explain the difference, I will first have to go back to regular spinning Hard Disk Drives (HDD). There are variances in manufacturing, so how do you make sure that a spinning disk has AT LEAST the amount of space you are selling it as? The solution is to include extra. This is the same way that rice, flour, and a variety of other commodities are sold. Legally, if it says you are buying a pound or kilo of flour, then it must be AT LEAST that much to be legal labeling. Including some extra is a safe way to comply with the law. In the case of disk capacity, having some spare capacity and the means to use it follows the same general concept.
(Disk capacity is measured in multiples of 1000, in this case a Gigabyte (GB) = 1,000,000,000 bytes, not to be confused with [Gibibyte (GiB)] = 1,073,741,824 bytes, based on multiples of 1024.)
Let's say a manufacturer plans to sell 146GB HDD. We know that in some cases there might be bad sectors on the disk that won't accept written data on day 1, and there are other marginally-bad sectors that might fail to accept written data a few years later, after wear and tear. A manufacturer might design a 156GB drive with 10GB of spare capacity and format this with a defective-sector table that redirects reads/writes of known bad sectors to good ones. When a bad sector is discovered, it is added to the table, and a new sector is assigned out of the spare capacity.Over time, the amount of space that a drive can store diminishes year after year, and once it drops below its rated capacity, it fails to meet its legal requirements. Based on averages of manufacturing runs and material variances, these could then be sold as 146GB drives, with a life expectancy of 3-5 years.
With Solid State Disk, the technology requires a lot of tricks and techniques to stay above the rated capacity. For example, you can format a 256GB drive as a conservative 146GB usable, with an additional 110GB (75 percent) spare capacity to handle all of the wear-leveling. You could lose up to 22GB of cells per year, and still have the rated capacity for the full five-year life expectancy.
Alternatively, you could take a more aggressive format, say 200GB usable, with only 56GB (28 percent) of spare capacity. If you lost 22GB of cells per year, then sometime during the third year, hopefully under warranty, your vendor could replace the drive with a fresh new one, and it should last the rest of the five year time frame. The failed drive, having 190GB or so usable capacity, could then be re-issued legally as a refurbished 146GB drive to someone else.
The wear and tear on SSD happens mostly during erase-write cycles, so for read-intensive workloads, such as boot disks for operating system images, the aggressive 200GB format might be fine, and might last the full five years.For traditional business applications (70 percent read, 30 percent write) or more write-intensive workloads, IBM feels the more conservative 146GB format is a safer bet.
This should be of no surprise to anyone. When it comes to the safety, security and integrity of our client's data, IBM has always emphasized the conservative approach.[Read More]