I am still wiping the coffee off my computer screen, inadvertently sprayed when I took a sip while reading HDS' uber-blogger Hu Yoshida's post on storage virtualization andvendor lock-in
. This blog appears to be the text version of theirfunny video
While most of the post is accurate and well-stated, two opinions particular caught my eye. I'll be nice and call them opinions, since these are blogs, and always subject to interpretation. I'll put quotes around them so that people will correctly relate these to Hu, and not me.
"Storage virtualization can only be done in a storage controller. Currently Hitachi is the only vendor to provide this."
-- Hu Yoshida
Hu, I enjoy all of your blog entries, but you should know better. HDS is fairly new-comer to the storage virtualization arena, so since IBM has been doing this for decades, I will bring you and the rest of the readers up to speed. I am not starting a blog-fight, just want to provide some additional information for clients to consider when making choices in the marketplace.
First, let's clarify the terminology. I will use 'storage' in the broad sense, including anything that can hold 1's and 0's, including memory, spinning disk media, and plastic tape media. These all have different mechanisms and access methods, based on their physical geometry and characteristics. The concept of 'virtualization' is any technology that makes one set of resources look like another set of resources with more preferable characteristics, and this applies to storage as well as servers and networks. Finally, 'storage controller' is any device with the intelligence to talk to a server and handle its read and write requests.
Second, let's take a look at all the different flavors of storage virtualization that IBM has developed over the past 30 years.
IBM introduces the S/370 with the OS/VS1 operating system. "VS" here refers to virtual storage, and in this case internal server memory was swapped out to physical disk. Using a table mapping, disk was made to look like an extension of main memory.
IBM introduces the IBM 3850 Mass Storage System (MSS). Until this time, programs that ran on mainframes had to be acutely aware of the device types being written, as each device type had different block, track and cylinder sizes, so a program written for one device type would have to be modified to work with a different device type. The MSS was able to take four 3350 disks, and a lot of tapes, and make them look like older 3330 disks, since most programs were still written for the 3330 format. The MSS was a way to deliver new 3350 disk to a 3330-oriented ecosystem, and greatly reduce the cost by handling tape on the back end. The table mapping was one virtual 3330 disk (100 MB) to two physical tapes (50 MB each). Back then, all of the mainframe disk systems had separate controllers. The 3850 used a 3831 controller that talked to the servers.
IBM invents Redundant Array of Independent Disk (RAID) technology. The table mapping is one or more virtual "Logical Units" (or "LUNs") to two or more physical disks. Data is striped, mirrored and paritied across the physical drives, making the LUNs look and feel like disks, but with faster performance and higher reliability than the physical drives they were mapped to. RAID could be implemented in the server as software, on top or embedded into the operating system, in the host bus adapter, or on the controller itself. The vendor that provided the RAID software or HBA did not have to be the same as the vendor that provided the disk, so in a sense, this avoided "vendor lock-in".Today, RAID is almost always done in the external storage controller.
IBM introduces the Personal Computer. One of the features of DOS is the ability to make a "RAM drive". This is technology that runs in the operating system to make internal memory look and feel like an external drive letter. Applications that already knew how to read and write to drive letters could work unmodified with these new RAM drives. This had the advantage that the files would be erased when the system was turned off, so it was perfect for temporary files. Of course, other operating systems today have this feature, UNIX has a /tmp directory in memory, and z/OS uses VIO storage pools.
This is important, as memory would be made to look like disk externally, as "cache", in the 1990s.
IBM AIX v3 introduces Logical Volume Manager (LVM). LVM maps the LUNs from external RAID controllers into virtual disks inside the UNIX server. The mapping can combine the capacity of multiple physical LUNs into a large internal volume. This was all done by software within the server, completely independent of the storage vendor, so again no lock-in.
IBM introduces the Virtual Tape Server (VTS). This was a disk array that emulated a tape library. A mapping of virtual tapes to physical tapes was done to allow full utilization of larger and larger tape cartridges. While many people today mistakenly equate "storage virtualization" with "disk virtualization", in reality it can be implemented on other forms of storage. The disk array was referred to as the "Tape Volume Cache". By using disk, the VTS could mount an empty "scratch" tape instantaneously, since no physical tape had to be mounted for this purpose.
Contradicting its "tape is dead" mantra, EMC later developed its CLARiiON disk library that emulates a virtual tape library (VTL).
IBM introduces the SAN Volume Controller. It involves mapping virtual disks to manage disks that could be from different frames from different vendors. Like other controllers, the SVC has multiple processors and cache memory, with the intelligence to talk to servers, and is similar in functionality to the controller components you might find inside monolithic "controller+disk" configurations like the IBM DS8300, EMC Symmetrix, or HDS TagmaStore USP. SVC can map the virtual disk to physical disk one-for-one in "image mode", as HDS does, or can also map virtual disks across physical managed disks, using a similar mapping table, to provide advantages like performance improvement through striping. You can take any virtual disk out of the SVC system simply by migrating it back to "image mode" and disconnecting the LUN from management. Again, no vendor lock-in.
The HDS USP and NSC can run as regular disk systems without virtualization, or the virtualization can be enabled to allow external disks from other vendors. HDS usually counts all USP and NSC sold, but never mention what percentage these have external disks attached in virtualization mode. Either they don't track this, or too embarrassed to publish the number. (My guess: single digit percentage).
Few people remember that IBM also introduced virtualization in both controller+disk and SAN switch form factors. The controller+disk version was called "SAN Integration Server", but people didn't like the "vendor lock-in" having to buy the internal disk from IBM. They preferred having it all external disk, with plenty of vendor choices. This is perhaps why Hitachi now offers a disk-less version of the NSC 55, in an attempt to be more like IBM's SVC.
IBM also had introduced the IBM SVC for Cisco 9000 blade. Our clients didn't want to upgrade their SAN switch networking gear just to get the benefits of disk virtualization. Perhaps this is the same reason EMC has done so poorly with its "Invista" offering.
So, bottom line, storage virtualization can, and has, been delivered in the operating system software, in the server's host bus adapter, inside SAN switches, and in storage controllers. It can be delivered anywhere in the path between application and physical media. Today, the two major vendors that provide disk virtualization "in the storage controller" are IBM and HDS, and the three major vendors that provide tape virtualization "in the storage controller" are IBM, Sun/STK, and EMC. All of these involve a mapping of logical to physical resources. Hitachi uses a one-for-one mapping, whereas IBM additionally offers more sophisticated mappings as well.
technorati tags: IBM, disk, tape, storage, virtualization, Hu Yoshia, HDS, Hitachi, TagmaStore, USP, NSC, disk-less, SAN Volume Controller, LVM, AIX, RAID, SAN, blade, Sun, STK, Cisco, EMC, Invista,
Last week, in my posting on Toshiba's latest 1.8" drive
, Robert Pearson asks:
You may not be the right person to ask but I am asking everyone so "How do you see hybrid disk drives?"
(For the record, I am not immediately related to Robert. At onepoint, "Pearson" was the 12th most common surname in the USA, but now doesn't even make the Top 100.)
Robert, I would like to encourage you and everyone else to ask questions, don't worry if I am the wrong person to ask, asprobably I know the right person within IBM. Some people have called me the "Kevin Bacon" of Storage,as I am often less than six degrees away from the right person, having worked in IBM Storage for over 20 years.
For those not familiar with hybrid drives, there is a good write-up in Wikipedia.
Unfortunately, most of the people I would consult on this question, such as those from Market Intelligence or Research, are on vacation for the holidays, so, Robert, I will have to rely on my trusted 78-card Tarot deck and answer you with a five-card throw.
- Your first card, Robert, is the Hermit. This card represents "introspection". The best I/O is no I/O, which means that if applications can keep the information they need inside server memory, you can avoid the bus bandwidth limitations to going to external storage devices. Where external storage makes sense is when data is shared between servers, or when the single server is limited to a set amount of internal memory. So, consider maxing out the memory in your server first (IBM would be glad to sell you more internal memory!!!), then consider outside solid-state or hybrid devices. Windows for example has an architectural limit of 4GB.
- Your second card, Robert, is the Four of Cups, representing "apathy".On the card, you see three cups together, with the fourth cup being delivered from a cloud. This reminds me thatwe have three storage tiers already (memory,disk,tape), and introducing a fourth tier into the mix may not garnermuch excitement. For the mainframe, IBM introduced a Solid-State Device, call the Coupling Facility, which can be accessed from multipleSystem z servers. It is used heavily by DFSMS and DB2 to hold shared information. However, given some customer's apathytowards Information Lifecycle Management which includes "tiered storage", introducing yet another tier that forcespeople to decide what data goes where may be another challenge.
- Your third card, Robert, is the Chariot, which represents "Speed, Determination,and Will". In some cases, solid state disk are faster for reading, but can be slower for writing. In the case of ahybrid drive, where the memory acts as a front-end cache, read-hits would be faster, but read-misses might be slower.While the idea of stopping the drives during inactivity will reduce power consumption, spinning up and slowing downthe disk may incur additional performance penalties. At the time of this post, the fastest disk system remains the IBM SAN Volume Controller, based on SPC-1 and SPC-2 benchmarks in excess of those published for other devices.
- Your fourth card, Robert, is the Eight of Pentacles, which represents"Diligence, Hard work". The pentacles are coins with five-sided stars on them, and this often represents money.Our research team has projected that spinning disk will continue to be a viable and profitable storage media for at least anothereight years.
- Your fifth and last card, Robert, is the World, which normallyrepresents "Accomplishment", but since it is turned upside down, the meaning is reversed to "Limitation". Some Hybriddisks, and some types of solid state memory in general, do have limitations in the number of write cycles they can handle. For thoseunhappy with the frequency and slowness for rebuilds on SATA disk may find similar problems with hybrid drives.For that reason, businesses may not trust using hybrid drives for their busiest, mission-critical applications, but certainlymight use it for archive data with lower write-cycle requirements.
The tarot cards are never wrong, but certainly interpretations of the cards can be.
technorati tags: Robert Pearson, Kevin Bacon, IBM, storage, Tarot, card, deck, Hermit, Four-of-Cups, Coupling Facility, Chariot, SAN Volume Controller, SVC, SPC-1, SPC-2, benchmarks, Texas Memory Systems, Eight-of-Pentacles, World, Hybrid, SATA
Jon Toigo has a funny cartoon on his post, [As I Listen to EMC Brag on “New” Functionality…
]. Basically, it pokes fun that many of us bloggers argue which vendor was first to introduce some technology or another. We all do this, myself included.
Recently, Claus Mikkelsen's, currently with HDS, [brought up accurately some past history from the 1990s], which is before many storage bloggers hired on with their current employers. Claus and I worked together for IBM back then, so I recognized many of the events he mentions that I can't talk about either. In many cases, IBM or HDS delivered new features before EMC.
I've been reading with some amusement as fellow blogger Barry Burke asked Claus a series of questions about Hitachi's latest High Availability Manager (HAM) feature. Claus was too busy with his "day job" and chose to shut Barry down. Sadly, HDS set themselves up for ridicule this round, first by over-hyping a function before its announcement, and then announcing a feature that IBM and EMC have offered for a while. The problem and confusion for many is that each vendor uses different terminology. Hitachi's HAM is similar to IBM's HyperSwap and EMC's AutoSwap. The implementations are different, of course, which is often why vendors are often asked to compare and contrast one implementation to another.
In his latest response,[how to mind the future of a mission-critical world], Barry reports that several HDS bloggers now censor his comments.That's too bad. I don't censor comments, within reason, including Barry's inane questions about IBM's products, and am glad that he does not censor my inane questions to him about EMC products in return. The entire blogosphere benefits from these exchanges, even if they are a bit heated sometimes.
We all have day jobs, and often are just too busy, or too lazy, to read dozens or hundreds of pages of materials, if we can even find them in the first place. Not everyone has the luxury of a "competitive marketing" team to help do the research for you, so if we can get an accurate answer or clarification about a product that is generally available directly from a vendor's subject matter expert, I am all for that.
technorati tags: IBM, Jon Toigo, HDS, Claus Mikkelsen, EMC, Barry Burke, HAM
It's official! My "blook" Inside System Storage - Volume I
is now available.
|This blog-based book, or “blook”, comprises the first twelve months of posts from this Inside System Storage blog,165 posts in all, from September 1, 2006 to August 31, 2007. Foreword by Jennifer Jones. 404 pages.|
- IT storage and storage networking concepts
- IBM strategy, hardware, software and services
- Disk systems, Tape systems, and storage networking
- Storage and infrastructure management software
- Second Life, Facebook, and other Web 2.0 platforms
- IBM’s many alliances, partners and competitors
- How IT storage impacts society and industry
You can choose between hardcover (with dust jacket) or paperback versions:
This is not the first time I've been published. I have authored articles for storage industry magazines, written large sections of IBM publications and manuals, submitted presentations and whitepapers to conference proceedings, and even had a short story published with illustrations by the famous cartoon writer[Ted Rall].
But I can say this is my first blook, and as far as I can tell, the first blook from IBM's many bloggers on DeveloperWorks, and the first blook about the IT storage industry.I got the idea when I saw [Lulu Publishing] run a "blook" contest. The Lulu Blooker Prize is the world's first literary prize devoted to "blooks"--books based on blogs or other websites, including webcomics. The [Lulu Blooker Blog] lists past year winners. Lulu is one of the new innovative "print-on-demand" publishers. Rather than printing hundredsor thousands of books in advance, as other publishers require, Lulu doesn't print them until you order them.
I considered cute titles like A Year of Living Dangerously, orAn Engineer in Marketing La-La land, or Around the World in 165 Posts, but settled on a title that matched closely the name of the blog.
In addition to my blog posts, I provide additional insights and behind-the-scenes commentary. If you go to the Luluwebsite above, you can preview an entire chapter in its entirety before purchase. I have added a hefty 56-page Glossary of Acronyms and Terms (GOAT) with over 900 storage-related terms defined, which also doubles as an index back to the post (or posts) that use or further explain each term.
So who might be interested in this blook?
- Business Partners and Sales Reps looking to give a nice gift to their best clients and colleagues
- Managers looking to reward early-tenure employees and retain the best talent
- IT specialists and technicians wanting a marketing perspective of the storage industry
- Mentors interested in providing motivation and encouragement to their proteges
- Educators looking to provide books for their classroom or library collection
- Authors looking to write a blook themselves, to see how to format and structure a finished product
- Marketing personnel that want to better understand Web 2.0, Second Life and social networking
- Analysts and journalists looking to understand how storage impacts the IT industry, and society overall
- College graduates and others interested in a career as a storage administrator
And yes, according to Lulu, if you order soon, you can have it by December 25.
technorati tags: IBM, blook, Volume I, Jennifer Jones, system, storage, strategy, hardware, software, services, disk, tape, networking, SAN, secondlife, Web2.0, facebook, Lulu, publishing, Blooker Prize, articles, magazines, proceedings, Ted Rall, insights, glossary, early-tenure, mentors, library, classroom, administrator, print, publish, on demand
In North America, today marks the start of the "Give 1 Get 1" program.
|Children using the XO laptop|
I first learned from this when I was reading about Timothy Ferriss' [LitLiberation project] on his [Four Hour Work Week] blog, and was surfing around for related ideas, and chanced upon this. I registered for a reminder, and it came today(the reminder, not the laptop itself).
Here's how the program works. You give $399 US dollars to the "One Laptop per Child" (OLPC)[laptop.org] organization for two laptops: One goes to a deserving child ina developing country, the second goes to you, for your own child, or to donate to a localcharity that helps children. This counts as a $199 purchase plus a $200 tax-deductible donation.For Americans, this is a [US 501(c)(3)] donation, and for Canadians and Mexicans, take advantage of the low-value of the US dollar!
If your employer matches donations, like IBM does, get them to match the $200donation for a third laptop, which goes to another child in a developing country. As for shipping, you pay only for the shipping of the one to you, each receiving country covers their own shipping. In my case, the shipping was another $24 US dollars for Arizona.No guarantees that it will arrive in time for the holidays this December, but it might.
To sweeten the deal, T-mobile throws in a year's worth of "Wi-Fi Hot Spot"that you can use for yourself, either with the XO laptop itself, or your regular laptop, iPhone, or otherWi-Fi enabled handheld device.
National Public Radio did a story last week on this:[The $100 Laptop Heads for Uganda]where they interview actor [Masi Oka], best known from the TV show ["Heroes"], who has agreed to be their spokesman.At the risk of sounding like their other spokesman, I thought I would cover the technology itself, inside the XO,and how this laptop represents IBM's concept of "Innovation that matters"!
The project was started by [Nicholas Negroponte] from [MIT University] as the "$100 laptop project". Once the final designwas worked out, it turns out it costs $188 US dollars to make, so they rounded it up to $200. This is stillan impressive price, and requires that hundreds of thousands of them be manufactured to justify ramping upthe assembly line.
Two of IBM's technology partners are behind this project. First is Advanced Micro Devices (AMD) that providesthe 433Mhz x86 processor, which is 75 percent slower than Thinkpad T60. Second is Red Hat,as this runs lean Fedora 6 version of Linux. Obviously, you couldn't have Microsoft Windows or Apple OS X, as both require significantly more resources.
The laptop is "child size", and would be considered in the [subnotebook] category. At 10" x 9" x 1.25", it is about the size of class textbook,can be carried easily in a child's backpack, or carried by itself with the integrated handle. When closed, it is sealedenough to be protected when carried in rain or dust storms. It weighs about 3.5 pounds, less than the 5.2 pounds of myThinkpad T60.
The XO is "green", not just in color, but also in energy consumption.This laptop can be powered by AC, or human power hand-crank, with workin place to get options for car-battery or solar power charging. Compared to the 20W normally consumed bytraditional laptops, the XO consumes 90 percent less, running at 2W or less. To accomplish this, there is no spinning disk inside. Instead, a 1GB FLASH drive holds 700MB of Linux, and gives you 300MB to hold your files. There isa slot for an MMC/SD flash card, and three USB 2.0 ports to connect to USB keys, printers or other remote I/O peripherals.
The XO flips around into three positions:
Standard laptop position has screen and keyboard. The water-tight keyboard comes in ten languages:International/English, Thai, Arabic, Spanish, Portuguese, West African, Urdu, Mongolian, Cyrillic, and Amharic.(I learned some Amharic, having lived five years with Ethiopians.)There does not appear be a VGA port, so don't be thinking this could be used as an alternative to project Powerpoint presentations onto a big screen.
Built-in 640x480 webcam, microphone and speakers allow the XO to be used as a communication device. Voice-over-IP (VOIP) client software, similar to Skype or [IBM Lotus Sametime], is pre-installed for this purpose.
The basic built-in communication are 802.1g (54Mbs) that you can use to surf the web usingthe Wi-Fi at your local Starbucks; and 802.1s which forms a "mesh network" with other XO laptops, and can surf theweb finding the one laptop nearby that is connected to the internet to share bandwidth. This eliminates the need to build a separate Wi-Fi hub at the school. There are USB-to-Ethernet and USB-to-Cellular converters, so that might be an alternative option.
Flipped vertically, the device can be read like a book.The screen can be changed between full-color and black-white, 200 dpi, with decent 1200x900 pixel resolution. The full-color is back-lit, and can be read in low-lighting. The black-white is not back-lit, consumes much less power, andcan be read in bright sunlight. In that regards, it is comparable to other [e-book devices], like a Cybook or Sony Reader.
Software includes a web-browser, document reader, word processor and RSS feed reader to read blogs.The OLPC identifies all of the software, libraries and interfaces they use, so that anyone that wants to developchildren software for this platform can do so.
- Game mode
With the keyboard flipped back, the 6" x 4.5" screen has directional controls and X/Y/A/B buttons to run games. This would make it comparable to a Nintendo DS or Playstation Portable (PSP). Again, the choice between back-lit color,or sunlight black-white screen modes apply. Some games are pre-installed.
So for $399, you could buy a Wi-Fi enabled[16GB iPod Touch
] for yourself, which does much the same thing, or you can make a difference in the world.I made my donation this morning, and suggest you--my dear readers in the US, Canada and Mexico--consider doing the same.Go to [www.laptopgiving.org
] for details.
Well, this week I am in Maryland, just outside of Washington DC. It's a bit cold here.
Robin Harris over at StorageMojo put out this Open Letter to Seagate, Hitachi GST, EMC, HP, NetApp, IBM and Sun about the results of two academic papers, one from Google, and another from Carnegie Mellon University (CMU). The papers imply that the disk drive module (DDM) manufacturers have perhaps misrepresented their reliability estimates, and asks major vendors to respond. So far, NetAppand EMC have responded.
I will not bother to re-iterate or repeat what others have said already, but make just a few points. Robin, you are free to consider this "my" official response if you like to post it on your blog, or point to mine, whatever is easier for you. Given that IBM no longer manufacturers the DDMs we use inside our disk systems, there may not be any reason for a more formal response.
- Coke and Pepsi buy sugar, Nutrasweet and Splenda from the same sources
Somehow, this doesn't surprise anyone. Coke and Pepsi don't own their own sugar cane fields, and even their bottlers are separate companies. Their job is to assemble the components using super-secret recipes to make something that tastes good.
IBM, EMC and NetApp don't make DDMs that are mentioned in either academic study. Different IBM storage systems uses one or more of the following DDM suppliers:
- Seagate (including Maxstor they acquired)
- Hitachi Global Storage Technologies, HGST (former IBM division sold off to Hitachi)
In the past, corporations like IBM was very "vertically-integrated", making every component of every system delivered.IBM was the first to bring disk systems to market, and led the major enhancements that exist in nearly all disk drives manufactured today. Today, however, our value-add is to take standard components, and use our super-secret recipe to make something that provides unique value to the marketplace. Not surprisingly, EMC, HP, Sun and NetApp also don't make their own DDMs. Hitachi is perhaps the last major disk systems vendor that also has a DDM manufacturing division.
So, my point is that disk systems are the next layer up. Everyone knows that individual components fail. Unlike CPUs or Memory, disks actually have moving parts, so you would expect them to fail more often compared to just "chips".
If you don't feel the MTBF or AFR estimates posted by these suppliers are valid, go after them, not the disk systems vendors that use their supplies. While IBM does qualify DDM suppliers for each purpose, we are basically purchasing them from the same major vendors as all of our competitors. I suspect you won't get much more than the responses you posted from Seagate and HGST.
- American car owners replace their cars every 59 months
According to a frequently cited auto market research firm, the average time before the original owner transfers their vehicle -- purchased or leased -- is currently 59 months.Both studies mention that customers have a different "definition" of failure than manufacturers, and often replace the drives before they are completely kaput. The same is true for cars. Americans give various reasons why they trade in their less-than-five-year cars for newer models. Disk technologies advance at a faster pace, so it makes sense to change drives for other business reasons, for speed and capacity improvements, lower power consumption, and so on.
The CMU study indicated that 43 percent of drives were replaced before they were completely dead.So, if General Motors estimated their cars lasted 9 years, and Toyota estimated 11 years, people still replace them sooner, for other reasons.
At IBM, we remind people that "data outlives the media". True for disk, and true for tape. Neither is "permanent storage", but rather a temporary resting point until the data is transferred to the next media. For this reason, IBM is focused on solutions and disk systems that plan for this inevitable migration process. IBM System Storage SAN Volume Controller is able to move active data from one disk system to another; IBM Tivoli Storage Manager is able to move backup copies from one tape to another; and IBM System Storage DR550 is able to move archive copies from disk and tape to newer disk and tape.
If you had only one car, then having that one and only vehicle die could be quite disrupting. However, companies that have fleet cars, like Hertz Car Rentals, don't wait for their cars to completely stop running either, they replace them well before that happens. For a large company with a large fleet of cars, regularly scheduled replacement is just part of doing business.
This brings us to the subject of RAID. No question that RAID 5 provides better reliability than having just a bunch of disks (JBOD). Certainly, three copies of data across separate disks, a variation of RAID 1, will provide even more protection, but for a price.
Robin mentions the "Auto-correlation" effect. Disk failures bunch up, so one recent failure might mean another DDM, somewhere in the environment, will probably fail soon also. For it to make a difference, it would (a) have to be a DDM in the same RAID 5 rank, and (b) have to occur during the time the first drive is being rebuilt to a spare volume.
- The human body replaces skin cells every day
So there are individual DDMs, manufactured by the suppliers above; disk systems, manufactured by IBM and others, and then your entire IT infrastructure. Beyond the disk system, you probably have redundant fabrics, clustered servers and multiple data paths, because eventually hardware fails.
People might realize that the human body replaces skin cells every day. Other cells are replaced frequently, within seven days, and others less frequently, taking a year or so to be replaced. I'm over 40 years old, but most of my cells are less than 9 years old. This is possible because information, data in the form of DNA, is moved from old cells to new cells, keeping the infrastructure (my body) alive.
Our clients should approach this in a more holistic view. You will replace disks in less than 3-5 years. While tape cartridges can retain their data for 20 years, most people change their tape drives every 7-9 years, and so tape data needs to be moved from old to new cartridges. Focus on your information, not individual DDMs.
What does this mean for DDM failures. When it happens, the disk system re-routes requests to a spare disk, rebuilding the data from RAID 5 parity, giving storage admins time to replace the failed unit. During the few hours this process takes place, you are either taking a backup, or crossing your fingers.Note: for RAID5 the time to rebuild is proportional to the number of disks in the rank, so smaller ranks can be rebuilt faster than larger ranks. To make matters worse, the slower RPM speeds and higher capacities of ATA disks means that the rebuild process could take longer than smaller capacity, higher speed FC/SCSI disk.
According to the Google study, a large portion of the DDM replacements had no SMART errors to warn that it was going to happen. To protect your infrastructure, you need to make sure you have current backups of all your data. IBM TotalStorage Productivity Center can help identify all the data that is "at risk", those files that have no backup, no copy, and no current backup since the file was most recently changed. A well-run shop keeps their "at risk" files below 3 percent.
So, where does that leave us?
- ATA drives are probably as reliable as FC/SCSI disk. Customers should chose which to use based on performance and workload characteristics. FC/SCSI drives are more expensive because they are designed to run at faster speeds, required by some enterprises for some workloads. IBM offers both, and has tools to help estimate which products are the best match to your requirements.
- RAID 5 is just one of the many choices of trade-offs between cost and protection of data. For some data, JBOD might be enough. For other data that is more mission critical, you might choose keeping two or three copies. Data protection is more than just using RAID, you need to also consider point-in-time copies, synchronous or asynchronous disk mirroring, continuous data protection (CDP), and backup to tape media. IBM can help show you how.
- Disk systems, and IT environments in general, are higher-level concepts to transcend the failures of individual components. DDM components will fail. Cache memory will fail. CPUs will fail. Choose a disk systems vendor that combines technologies in unique and innovative ways that take these possibilities into account, designed for no single point of failure, and no single point of repair.
So, Robin, from IBM's perspective, our hands are clean. Thank you for bringing this to our attention and for giving me the opportunity to highlight IBM's superiority at the systems level.
technorati tags: IBM, Seagate, Hitachi, HGST, EMC, NetApp, HP, HDS, Sun, Google, CMU, DDM, Fujitsu, MTBF, MTTF, AFR, ARR, JBOD, RAID, Tivoli, SVC, DR550, CDP, FC, SCSI, disk, tape, SAN,
After my response to Jon Toigo on Drunken Data
withmy post [Elevenanswers about Deduplication
], Jon follows up with a request to validate the numbersquoted in the February 26 Press Release[IBM launches New “System z10” Mainframe
], particularly the estimate that a single mainframecan handle to the workload of 1500 x86 servers, in his post[A Bit More Blegging
]. The timing is perfect in that IBM launched[the next wave of Project Big Green
] today.To avoid sounding like an [editorial from the New York Sun
],I checked the facts, and spoke to the person in IBM who did all the calculations. Jon, as always, you have my permissionto publish this on your site if you want.
( I cannot take credit for coining the new term "bleg". I saw this term firstused over on the [FreakonomicsBlog]. If you have not yet read the book "Freakonomics", I highly recommend it! The authors' blog is excellent as well.)
For this comparison, it is important to figure out how much workload a mainframe can support, how much an x86 cansupport, and then divide one from the other. Sounds simple enough, right? And what workload should you choose?IBM chose a business-oriented "data-intensive" workload using Oracle database. (If you wanted instead a scientific"compute-intensive" workload, consider an [IBM supercomputer] instead, the most recent of which clocked in over 1 quadrillion floating point operations per second, or PetaFLOP.) IBM compares the following two systems:
- Sun Fire X2100 M2, model 1220 server (2-way)
IBM did not pick a wimpy machine to compare against. The model 1220 is the fastest in the series, with a 2.8Ghz x86-64 dual-core AMD Opteron processor, capable of running various levels of Solaris, Linux or Windows.In our case, we will use Oracle workloads running on Red Hat Enterprise Linux.All of the technical specifications are available at the[Sun Microsystems Sun Fire X1200] Web site.I am sure that there are comparable models from HP, Dell or even IBM that could have been used for this comparison.
- IBM z10 Enterprise Class mainframe model E64 (64-way)
This machine can run a variety of operating systems also, including Red Hat Enterprise Linux (RHEL). The E64 has four "multiple processor modules" called"processor books" for a total of 77 processing units: 64 central processors, 11 system assist processors (SAP) and 2 spares. That's right, spare processors, in case any others gobad, IBM has got your back. You can designate a central processor in a variety of flavors. For running z/VM and Linux operating systems, the central processors can be put into "Integrated Facility for Linux" (IFL) mode.On IT Jungle, Timothy Patrick Morgan explains the z10 EC in his article[IBM Launches 64-Way z10 Enterprise Class Mainframe Behemoth]. For more information on the z10 EC, see the 110-page [Technical Introduction], orread the specifications on the[IBM z10 EC] Web site.
Moving Oracle workloads from x86 over to mainframe is quite commonsince [IBM and Cisco joined forces to meet Linux On Mainframe demand]. For more information on consolidating x86 servers running Oracle over to a mainframe, read the [Quick Reference], IBMRedbook titled ["Using Oracle Solutionson Linux for System z"], or this [presentation by Jim Elliott, IBM System z Specialist].
In a shop full of x86 servers, there are production servers, test and development servers, quality assuranceservers, standby idle servers for high availability, and so on. On average, these are only 10 percent utilized.For example, consider the following mix of servers:
- 125 Production machines running 70 percent busy
- 125 Backup machines running idle ready for active failover in case a production machine fails
- 1250 machines for test, development and quality assurance, running at 5 percent average utilization
While [some might question, dispute or challenge thisten percent] estimate, it matches the logic used to justify VMware, XEN, Virtual Iron or other virtualization technologies. Running 10 to 20 "virtual servers" on a single physical x86 machine assumes a similar 5-10 percent utilization rate.
Note: The following paragraphs have been revised per comments received.
|Now the math. Jon, I want to make it clear I was not involved in writing the press release nor assisted with thesemath calculations. Please, don't shoot the messenger! Remember this cartoon where two scientists in white lab coats are writing mathcalculations on a chalkboard, and in the middle there is "and then a miracle happens..." to continue the rest ofthe calculations?|
In this case, the miracle is the number that compares one server hardware platform to another. I am not going to bore people with details like the number of concurrent processor threads or the differencesbetween L1 and L3 cache. IBM used sophisticated tools and third party involvement that I am not allowed to talk about, and I have discussed this post with lawyers representing
four (now five) different organizations already,so for the purposes of illustration and explanation only, I have reverse-engineered a new z10-to-Opteron conversion factor as 6.866 z10 EC MIPS per GHz of dual-core AMD Opteron for I/O-intensive workloads running only 10 percent average CPU utilization. Business applications that perform a lot of I/O don't use their CPU as much as other workloads.For compute-intensive or memory-intensive workloads, the conversion factor may be quite different, like 200 MIPS per GHz, as Jeff Savit from Sun Microsystems points out in the comments below.
Keep in mind that each processor is different, and we now have Intel, AMD, SPARC, PA-RISC and POWER (and others); 32-bit versus 64-bit; dual-core and quad-core; and different co-processor chip sets to worry about. AMD Opteron processors come in different speeds, but we are comparing against the 2.8GHz, so 1500 times 6.866 times 2.8 is 28,337. Since these would be running as Linux guestsunder z/VM, we add an additional 7 percent overhead or 2,019 MIPS. We then subtract 15 percent for "smoothing", whichis what happens when you consolidate workloads that have different peaks and valleys in workload, or 4,326 MIPS.The end is that we need a machine to do 26,530 MIPS. Thanks to advances in "Hypervisor" technological synergy between the z/VM operating system and the underlying z10 EC hardware, the mainframe can easily run 90 percent utilized when aggregating multiple workloads, so a 29,477 MIPS machine running at 90 percent utilization can handle these 26,530 MIPS.
N-way machines, from a little 2-way Sun Fire X2100 to the might 64-way z10 EC mainframe, are called "Symmetric Multiprocessors". All of the processors or cores are in play, but sometimes they have to taketurns, wait for exclusive access on a shared resource, such as cache or the bus. When your car is stopped at a red light, you are waiting for your turn to use the shared "intersection". As a result, you don't get linear improvement, but rather you get diminishing returns. This is known generically as the "SMP effect", and in IBM documentsthis as [Large System Performance Reference].While a 1-way z10 EC can handle 920 MIPS, the 64-way can only handle30,657 MIPS. The 29,477 MIPS needed for the Sun x2100 workload can be handled by a 61-way, giving you three extraprocessors to handle unexpected peaks in workload.
But are 1500 Linux guest images architecturally possible? A long time ago, David Boyes of[Sine Nomine Associates] ran 41,400 Linux guest images on a single mainframe using his [Test Plan Charlie], and IBM internallywas able to get 98,000 images, and in both cases these were on machines less powerful than the z10 EC. Neitherof these were tests ran I/O intensive workloads, but extreme limits are always worth testing. The 1500-to-1 reduction in IBM's press release is edge-of-the-envelope as well, so in production environments, several hundred guest images are probably more realistic, and still offer significant TCO savings.
The z10 EC can handle up to 60 LPARs, and each LPAR can run z/VM which acts much like VMware in allowing multipleLinux guests per z/VM instance. For 1500 Linux guests, you could have 25 guests each on 60 z/VM LPARs, or 250 guests on each of six z/VM LPARs, or 750 guests on two LPARs. with z/VM 5.3, each LPAR can support up to 256GB of memory and 32 processors, so you need at least two LPAR to use all 64 engines. Also, there are good reasons to have different guests under different z/VM LPARs, such as separating development/test from production workloads. If you had to re-IPLa specific z/VM LPAR, it could be done without impacting the workloads on other LPARs.
To access storage, IBM offers N-port ID Virtualization (NPIV). Without NPIV, two Linux guest images could not accessthe same LUN through the same FCP port because this would confuse the Host Bus Adapter (HBA), which IBM calls "FICON Express" cards. For example, Linux guest 1 asks to read LUN 587 block 32 and this is sent out a specific port, to a switch, to a disk system. Meanwhile, Linux guest 2 asks to read LUN 587 block 49. The data comes back to the z10 EC with the data, gives it to the correct z/VM LPAR, but then what? How does z/VM know which of the many Linux guests to give the data to? Both touched the same LUN, so it is unclear which made the request. To solve this, NPIV assigns a virtual "World Wide Port Name" (WWPN), up to 256 of them per physical port, so you can have up to 256 Linux guests sharing the same physical HBA port to access the same LUN.If you had 250 guests on each of six z/VM LPARs, and each LPAR had its own set of HBA ports, then all 1500 guestscould access the same LUN.
Yes, the z10 EC machines support Sysplex. The concept is confusing, but "Sysplex" in IBM terminology just means that you can have LPARs either on the same machine or on separate mainframes, all sharing the same time source, whether this be a "Sysplex Timer" or by using the "Server Time Protocol" (STP). The z10 EC can have STP over 6 Gbps Infiniband over distance. If you wantedto have all 1500 Linux guests time stamp data identically, all six z/VM LPARs need access to the shared time source. This can help in a re-do or roll-back situation for Oracle databases to complete or back-out "Units of Work" transactions. This time stamp is also used to form consistency groups in "z/OS Global Mirror", formerly called "XRC" for Extended Remote Distance Copy. Currently, the "timestamp" on I/O applies only to z/OS and Linux and not other operating systems. (The time stamp is done through the CDK driver on Linux, and contributed back to theopen source community so that it is available from both Novell SUSE and Red Hat distributions.)To have XRC have consistency between z/OS and Linux, the Linux guests would need to access native CKD volumes,rather than VM Minidisks or FCP-oriented LUNs.
Note: this is different than "Parallel Sysplex" which refers to having up to 32 z/OS images sharing a common "Coupling Facility" which acts as shared memory for applications. z/VM and Linux do not participate in"Parallel Sysplex".
As for the price, mainframes list for as little as "six figures" to as much as several million dollars, but I have no idea how much this particular model would cost. And, of course, this is just the hardware cost. I could not find the math for the $667 per server replacement you mentioned, so don't have details on that.You would need to purchase z/VM licenses, and possibly support contracts for Linux on System z to be fully comparable to all of the software license and support costs of the VMware, Solaris, Linux and/or Windows licenses you run on the x86 machines.
This is where a lot of the savings come from, as a lot of software is licensed "per processor" or "per core", and so software on 64 mainframe processors can be substantially less expensive than 1500 processors or 3000 cores.IBM does "eat its own cooking" in this case. IBM is consolidating 3900 one-application-each rack-mounted serversonto 30 mainframes, for a ratio of 130-to-1 and getting amazingly reduced TCO. The savings are in the followingareas:
- Hardware infrastructure. It's not just servers, but racks, PDUs, etc. It turns out to be less expensive to incrementally add more CPU and storage to an existing mainframe than to add or replace older rack-em-and-stack-emwith newer models of the same.
- Cables. Virtual servers can talk to each other in the same machine virtually, such as HiperSockets, eliminatingmany cables. NPIV allows many guests to share expensive cables to external devices.
- Networking ports. Both LAN and SAN networking gear can be greatly reduced because fewer ports are needed.
- Administration. We have Universities that can offer a guest image for every student without having a majorimpact to the sys-admins, as the students can do much of their administration remotely, without having physicalaccess to the machinery. Companies uses mainframe to host hundreds of virtual guests find reductions too!
- Connectivity. Consolidating distributed servers in many locations to a mainframe in one location allows youto reduce connections to the outside world. Instead of sixteen OC3 lines for sixteen different data centers, you could have one big OC48 line instead to a single data center.
- Software licenses. Licenses based on servers, cores or CPUs are reduced when you consolidate to the mainframe.
- Floorspace. Generally, floorspace is not in short supply in the USA, but in other areas it can be an issue.
- Power and Cooling. IBM has experienced significant reduction in power consumption and cooling requirementsin its own consolidation efforts.
All of the components of DFSMS (including DFP, DFHSM, DFDSS and DFRMM) were merged into a single product "DFSMS for z/OS" and is now an included element in the base z/OS operating system. As a result of these, customers typically have 80 to 90 percent utilization on their mainframe disk. For the 1500 Linux guests, however, most of the DFSMS features of z/OS do not apply. These functions were not "ported over" to z/VM nor Linux on any platform.
Note: DFSMS can backup or dump Linux on System z partitions or volumes. See this [Appendix C. HOWTO backup Linux data through z/OS] for details.
Instead, the DFSMS concepts have been re-implemented into a new product called "Scale-Out File Services" (SOFS) which would provide NAS interfaces to a blendeddisk-and-tape environment. The SOFS disk can be kept at 90 percent utilization because policies can place data, movedata and even expire files, just like DFSMS does for z/OS data sets. SOFS supports standard NAS protocols such as CIFS,NFS, FTP and HTTP, and these could be access from the 1500 Linux guests over an Ethernet Network Interface Card (NIC), which IBM calls "OSA Express" cards.
Lastly, IBM z10 EC is not emulating x86 or x86-64 interfaces for any of these workloads. No doubt IBM and AMD could collaborate together to come up with an AMD Opteron emulator for the S/390 chipset, and load Windows 2003 right on top of it, but that would just result in all kinds of emulation overhead.Instead, Linux on System z guests can run comparable workloads. There are many Linux applications that are functionally equivalent or the same as their Windows counterparts. If you run Oracle on Windows, you could runOracle on Linux. If you run MS Exchange on Windows, you could run Bynari on Linux and let all of your Outlook Expressusers not even know their Exchange server had been moved! Linux guest images can be application servers, web servers, database servers, network infrastructure servers, file servers, firewall, DNS, and so on. For nearly any business workload you can assign to an x86 server in a datacenter, there is likely an option for Linux on System z.
Hope this answers all of your questions, Jon. These were estimates based on basic assumptions. This is not to imply that IBM z10 EC and VMware are the only technologies that help in this area, you can certainly find virtualization on other systems and through other software.I have asked IBM to make public the "TCO framework" that sheds more light on this.As they say, "Your mileage may vary."
For more on this series, check out the following posts:
If in your travels, Jon, you run into someone interested to see how IBM could help consolidate rack-mounted servers over to a z10 EC mainframe, have them ask IBM for a "Scorpion study". That is the name of the assessment that evaluates a specific clientsituation, and can then recommend a more accurate estimate configuration.
technorati tags: Jon Toigo, DrunkenData, bleg, IBM, z10, EC, E64, mainframe, x86, AMD, Opteron, Sun, Fire, X2100, petaFLOP, Freakonomics, Red Hat, RHEL, IFL, VMware, Jim Elliott, Xen, Virtual Iron, Solaris, Linux, Windows, Project Big Green, Infiniband, STP, Sysplex, Scorpion study, MS Exchange, Bynari, Oracle
Jon W Toigo over at Drunkendata has had a great set of posts on his skepticism of storage vendors touting their "green storage" solutions. My apologies for my"unnecessary" use of quotation marks
The ones I liked specifically were:
The last of which refers to this ComputerWorld article "EPA: U.S. needs more power plants to support data centers", which claims "from a technology perspective, the systems most responsible for gobbling up power are the relatively low-cost x86 servers ..." The article is based onthe recent EPA report that was just released.
Last month, in my post How manys Watts per Terabyte, I mentioned:
Some people find it surprising that it is often more cost-effective, and power-efficient, to run workloads on mainframe logical partitions (LPARs) than a stack of x86 servers running VMware.
Perhaps they won't be surprised any more. Here is an article in eWeek that explains how IBM isreducing energy costs 80% by consolidating 3,900 rack-optimized servers to 33 IBM System z mainframe servers, running Linux, in its own data centers. Since 1997, IBM has consolidated its 155 strategic worldwide data center locations down to just seven.
I am very pleased that IBM has invested heavily into Linux, with support across servers, storage, software andservices. Linux is allowing IBM to deliver clever, innovative solutions that may not be possible with other operating systems. If you are in storage, you should consider becoming more knowledgeable in Linux.
The older systems won't just end up in a landfill somewhere. Instead, the details are spelled out inthe IBM Press Release:
As part of the effort to protect the environment, IBM Global Asset Recovery Services, the refurbishment and recycling unit of IBM, will process and properly dispose of the 3,900 reclaimed systems. Newer units will be refurbished and resold through IBM's sales force and partner network, while older systems will be harvested for parts or sold for scrap. Prior to disposition, the machines will be scrubbed of all sensitive data. Any unusable e-waste will be properly disposed following environmentally compliant processes perfected over 20 years of leading environmental skill and experience in the area of IT asset disposition.
Whereas other vendors might think that some operational improvements will be enough, such as switching to higher-capacity SATA drives, or virtualizing x86 servers, IBM recognizes that sometimes more fundamental changes are required to effect real changes and real results.
technorati tags: Jon Toigo, Drunkendata, power, consumption, disk, systems, green, storage, Linux, consolidation, virtualization, recovery, services, landfill, SATA, x86, servers, eWeek, mainframe
People are confused over various orders of magnitude. News of the economic meltdownoften blurs the distinction between millions (10^6
), billions (10^9
), and trillions (10^12
).To show how different these three numbers are, consider the following:
- A million seconds ago - you might have received your last paycheck (12 days)
- A billion seconds ago - you were born or just hired on your current job (31 years)
- A trillion seconds ago - cavemen were walking around in Asia (31,000 years)
|That these numbers confuse the average person is no surprise, but that it confuses marketing people in the storage industry is even more hilarious. I am often correcting people who misunderstandMB (million bytes), GB (billion bytes) and TB (trillion bytes) of information.Take this graph as an example from a recent presentation.|
At first, it looks reasonable, back in 2004, black-and-white 2D X-Ray images were only 1MBin size when digitized, but by 2010 there will be fancy 4D images that now take 1TB, representinga 1000x increase. What?When I pointed out this discrepancy, the person who put this chart together didn't know what to fix.Were 4D images only 1GB in size, or was it really a 1000000x increase.
If a 2D image was 1000 by 1000 pixels, each pixel was a byte of information, then a 3D imagemight either be 1000 by 1000 by 1000 [voxels], or 1000 by 1000 at 1000 frames per second (fps). Thefirst being 3D volumetric space, and the latter called 2D+time in the medical field, the rest of us just say "video".4D images are 3D+time, volumetric scans over time, so conceivably these could be quite large in size.
The key point is that advances in medical equipment result in capturing more data, which canhelp provide better healthcare. This would be the place I normally plug an IBM product, like the Grid Medical Archive Solution [GMAS], a blended disk and tape storage solution designed specifically for this purpose.
So, as government agencies look to spend billions of dollars to provide millions of peoplewith proper healthcare, choosing to spend some of this money on a smarter infrastructure can result in creating thousands of jobs and save everyone a lot of money, but more importantly, save lives.
For more on this, check out Adam Christensen's blog post on[Smarter Planet], which points to a podcast byDr. Russ Robertson, chairman of the Counsel of Medical Education at Northwestern University’s Feinberg School of Medicine, and Dan Pelino, general manager of IBM's Healthcare and Life Sciences Industry.
technorati tags: IBM, smarter healthcare, 2D+time, 3D+time, 4D, medical images, Adam Christensen, Russ Robertson, Dan Pelino
Wrapping up this week's theme on ways to make the planet smarter, and less confusing, I present IBM's third annual [five in five
]. These are five IBM innovations to watch over the next five years, all of which have implications on information storage. Here is a quick [3-minute video
] that provides the highlights:
technorati tags: IBM, five-in-five, innovations, solar, health, talking Web, shopping assistants, forgetting