Safe Harbor Statement: The information on IBM products is intended to outline IBM's general product direction and it should not be relied on in making a purchasing decision. The information on the new products is for informational purposes only and may not be incorporated into any contract. The information on IBM products is not a commitment, promise, or legal obligation to deliver any material, code, or functionality. The development, release, and timing of any features or functionality described for IBM products remains at IBM's sole discretion.
Tony Pearson is a an active participant in local, regional, and industry-specific interests, and does not receive any special payments to mention them on this blog.
Tony Pearson receives part of the revenue proceeds from sales of books he has authored listed in the side panel.
Tony Pearson is not a medical doctor, and this blog does not reference any IBM product or service that is intended for use in the diagnosis, treatment, cure, prevention or monitoring of a disease or medical condition, unless otherwise specified on individual posts.
Tony Pearson is a Master Inventor and Senior IT Specialist for the IBM System Storage product line at the
IBM Executive Briefing Center in Tucson Arizona, and featured contributor
to IBM's developerWorks. In 2011, Tony celebrated his 25th year anniversary with IBM Storage on the same day as the IBM's Centennial. He is
author of the Inside System Storage series of books. This blog is for the open exchange of ideas relating to storage and storage networking hardware, software and services. You can also follow him on Twitter @az990tony.
(Short URL for this blog: ibm.co/Pearson
In my post yesterday [Spreading out the Re-Replication process], fellow blogger BarryB [aka The Storage Anarchist]raises some interesting points and questions in the comments section about the new IBM XIV Nextra architecture.I answer these below not just for the benefit of my friends at EMC, but also for my own colleagues within IBM,IBM Business Partners, Analysts and clients that might have similar questions.
If RAID 5/6 makes sense on every other platform, why not so on the Web 2.0 platform?
Your attempt to justify the expense of Mirrored vs. RAID 5 makes no sense to me. Buying two drives for every one drive's worth of usable capacity is expensive, even with SATA drives. Isn't that why you offer RAID 5 and RAID 6 on the storage arrays that you sell with SATA drives?
And if RAID 5/6 makes sense on every other platform, why not so on the (extremely cost-sensitive) Web 2.0 platform? Is faster rebuild really worth the cost of 40+% more spindles? Or is the overhead of RAID 6 really too much for those low-cost commodity servers to handle.
Let's take a look at various disk configurations, for example 3TB on 750GB SATA drives:
JBOD: 4 drives
JBOD here is industry slang for "Just a Bunch of Disks" and was invented as the term for "non-RAID".Each drive would be accessible independently, at native single-drive speed, with no data protection. Puttingfour drives in a single cabinet like this provides simplicity and convenience only over four separate drivesin their own enclosures.
RAID-10: 8 drives
RAID-10 is a combination of RAID-1 (mirroring) and RAID-0 (striping). In a 4x2 configuration, data is striped across disks 1-4,then these are mirrored across to disks 5-8. You get performance improvement and protection against a singledrive failure.
RAID-5: 5 drives
This would be a 4+P configuration, where there would be four drives' worth of data scattered across fivedrives. This gives you almost the same performance improvement as RAID-10, similar protection againstsingle drive failure, but with fewer drives per usable TB capacity.
RAID-6: 6 drives
This would be a 4+2P configuration, where the first P represents linear parity, and the second represents a diagonal parity. Similar in performance improvement as RAID-5, but protects against single and double drive failures, and still better than RAID-10 in terms of drives per TB usable capacity.
For all the RAID configurations, rebuild would require a spare drive, but often spares are shared among multiple RAID ranks, not dedicated to a single rank. To this end, you often have to have several spares per I/O loop, and a different set of spares for each kind of speed and capacity. If you had a mix of 15K/73GB, 10K/146GB, and 7200/500GB drives, then you would have three sets of spares to match.
In contrast, IBM XIV's innovative RAID-X approach doesn't requireany spare drives, just spare capacity on existing drives being used to hold data. The objects can be mirroredbetween any two types of drives, so no need to match one with another.
All of these RAID levels represent some trade-off between cost, protection and performance, and IBM offers each of theseon various disk systems platforms. Calculating parity is more complicated than just mirrored copies, but this can be done with specialized chips in cache memory to minimize performance impact.IBM generally recommends RAID-5 for high-performance FC disk, and RAID-6 for slower, large capacity SATA disk.
However, the questionassumes that the drive cost is a large portion of the overall "disk system" cost. It isn't. For example,Jon Toigo discusses the cost of EMC's new AX4 disk system in his post [National Storage Rip-Off Day]:
EMC is releasing its low end Clariion AX4 SAS/SATA array with 3TB capacity for $8600. It ships with four 750GB SATA drives (which you and I could buy at list for $239 per unit). So, if the disk drives cost $956 (presumably far less for EMC), that means buyers of the EMC wares are paying about $7700 for a tin case, a controller/backplane, and a 4Gbps iSCSI or FC connector. Hmm.
Dell is offering EMC’s AX4-5 with same configuration for $13,000 adding a 24/7 warranty.
(Note: I checked these numbers. $8599 is the list price that EMC has on its own website. External 750GB drivesavailable at my local Circuit City ranged from $189 to $329 list price. I could not find anything on Dell'sown website, but found [The Register] to confirm the $13,000 with 24x7 warranty figure.)
Disk capacity is a shrinking portion of the total cost of ownership (TCO). In addition to capacity, you are paying forcache, microcode and electronics of the system itself, along with software and services that are included in the mix,and your own storage administrators to deal with configuration and management. For more on this, see [XIV storage - Low Total Cost of Ownership].
EMC Centera has been doing this exact type of blob striping and protection since 2002
As I've noted before, there's nothing "magic" about it - Centera has been employing the same type of object-level replication for years. Only EMC's engineers have figured out how to do RAID protection instead of mirroring to keep the hardware costs low while not sacrificing availability.
I agree that IBM XIV was not the first to do an object-level architecture, but it was one of the first to apply object-level technologies to the particular "use case" and "intended workload" of Web 2.0 applications.
RAID-5 based EMC Centera was designed insteadto hold fixed-content data that needed to be protected for a specific period of time, such as to meet government regulatory compliance requirements. This is data that you most likelywill never look at again unless you are hit with a lawsuit or investigation. For this reason, it is important to get it on the cheapest storage configuration as possible. Before EMC Centera, customers stored this data on WORM tape and optical media, so EMC came up with a disk-only alternative offering.IBM System Storage DR550 offers disk-level access for themost recent archives, with the ability to migrate to much less expensive tape for the long term retention. The end result is that storing on a blended disk-plus-tape solution can help reduce the cost by a factor of 5x to 7x, making RAID level discussion meaningless in this environment. For moreon this, see my post [OptimizingData Retention and Archiving].
While both the Centera and DR550 are based on SATA, neither are designed for Web 2.0 platforms.When EMC comes out with their own "me, too" version, they will probably make a similar argument.
IBM XIV Nextra is not a DS8000 replacement
Nextra is anything but Enterprise-class storage, much less a DS8000 replacement. How silly of all those folks to suggest such a thing.
I did searches on the Web and could not find anybody, other than EMC employees, who suggested that IBM XIV Nextra architecture represented a replacement for IBM System Storage DS8000. The IBM XIV press release does not mentionor imply this, and certainly nobody I know at IBM has suggested this.
The DS8000 is designed for a different "use case" andset of "intended workloads" than what the IBM XIV was designed for. The DS8000 is the most popular disk systemfor our IBM System z mainframe platform, for activities like Online Transaction Processing (OLTP) and large databases, supporting ESCON and FICON attachment to high-speed 15K RPM FC drives. Web 2.0 customers that might chooseIBM XIV Nextra for their digital content might run their financial operations or metadata search indexes on DS8000.Different storage for different purposes.
As for the opinion that this is not "enterprise class", there are a variety of definitions that refer to this phrase.Some analysts look at "price band" of units that cost over $300,000 US dollars. Other analysts define this as beingattachable to mainframe servers via ESCON or FICON. Others use the term to refer to five-nines reliability, havingless than 5 minutes downtime per year. In this regard, based on the past two years experience at 40 customer locations,I would argue that it meets this last definition, with non-disruptive upgrades, microcode updates and hot-swappable components.
By comparison, when EMC introduced its object-level Centera architecture, nobody suggested it was the replacement for their Symmetrix or CLARiiON devices. Was it supposed to be?
Given drive growth rates have slowed, improving utilization is mandatory to keep up with 60-70 percent CAGR
Look around you, Tony- all of your competitors are implementing thin provisioning specifically to drive physical utilization upwards towards 60-80%, and that's on top of RAID 5/RAID 6 storage and not RAID 1. Given that disk drive growth rates and $/GB cost savings have slowed significantly, improving utilization is mandatory just to keep up with the 60-70% CAGR of information growth.
Disk drive capacities have slowed for FC disk because much of the attention and investment has been re-directed to ATA technology. Dollar-per-GB price reduction is slowing for disks in general, as researchers are hitting physicallimitations to the amount of bits they can pack per square inch of disk media, and is now around 25 percent per year.The 60-70 percent Compound Annual Growth Rate (CAGR) is real, and can be even growing faster for Web 2.0providers. While hardware costs drop, the big ticket items to watch will be software, services and storage administrator labor costs.
To this end, IBM XIV Nextra offers thin provisioning and differential space-efficient snapshots. It is designed for 60-90 percent utilization, and can be expanded to larger capacities non-disruptively in a very scalable manner.
I've gotten suggestions to upgrade the memory and disk storage, and how to fine-tune the Microsoft Windows XP operating system. Others suggested replacing the OS with Linux, and to use the Cloud to avoid some of the storage space limitations.
But first, I have to mention the latest in our series of "Enterprise Systems" videos. The first was being [Data Ready]. The second was being [Security Ready]. The now the third in the series: the 3-minute
[Cloud Ready] video.
So I decided to try different Cloud-oriented Operating Systems, to see if any would be a good fit. Here is what I found:
(FTC Disclosure: I work for IBM and own IBM stock. This blog post is not meant to endorse one OS over another. I have financial interests in, and/or have friends and family who work at some of the various companies mentioned in this post. Some of these companies also have business relationships with IBM.)
Jolicloud and Joli OS 1.2
I gave this OS a try. This is based on Linux, but with an interesting approach. First, you have to be on-line all the time, and this OS is designed for 15-25 year-olds who are on social media websites like Facebook. By having a Jolicloud account, you can access this from any browser on any system, or run the Joli OS operating system, or buy the already pre-installed Jolibook netbook computer.
The Joli OS 1.2 LiveCD ran fine on my T410 with 4GB or RAM, giving me a chance to check it out, but sadly did not run on grandma's Thinkpad R31 with 384MB of RAM. According to the [Jolicloud specifications], Joli OS should run in as little as 384MB of RAM and 2GB of disk storage space, but it didn't for me.
Google Chrome and Chromium OS Vanilla
Like the Jolibook, Google has come out with a $249 Chromebook laptop that runs their "Chrome OS". This is only available via OEM install on desginated hardware, but the open source version is available called Chromium OS. These are also based on Linux.
Rather than compiling from source, Hexxeh has made nightly builds available. You can download [Chromium OS Vanilla] zip file, unzip the image file, and copy it to a 4GB USB memory stick. The compressed image is about 300MB, but uncompressed about 2.5GB, so too big to fit on a CD. The image on the USB stick is actually two partitions, and cannot be run from DVD either.
If you don't have a 4GB USB stick handy, and want to see what all the fuss is about, just install the Google Chrome browser on your Windows or Linux system, and then maximize the browser window. That's it. That is basically what Chromium OS is all about.
Files can be stored locally, or out on your Google Drive. Documents can be edited using "Google Docs" in the Cloud. You can run in "off-line" mode, for example, read your Gmail notes when not connected to the Internet. Music and video files can be played using the "Files" app.
If you really need to get out of the browser, you can hit the right combination of keys to get to the "crosh" command line shell.
Like Joli OS, I was able to run this from my Thinkpad T410 with 4GB of RAM, but not on grandma's Thinkpad R31. It appears that Chromium requires at least 1GB of RAM to run properly.
Android for x86
While researching the Chromium OS, I found that there is an open source community porting [Android to the x86] platform. Android is based on Linux, and would allow your laptop or netbook to run very much like a smartphone or tablet. Most of the apps available to Android should work here as well.
Unfortunately, the project has focused only on selected hardware:
ASUS Eee PCs/Laptops
Viewsonic Viewpad 10
Dell Inspiron Mini Duo
Lenovo ThinkPad x61 Tablet
I tried running the Thinkpad x61 version on both my Thinkpad T410 and grandma's Thinkpad R31, but with no success.
Peppermint OS Three
Next up was Peppermint OS, which claims to be a blend of Linux Mint, Lubuntu, and Xfce, but with a "twist" of aspiring to be a Cloud-oriented OS.
Rather than traditional apps to write documents or maintain a calendar, this OS offers a "Single-Site Browser" (SSB) experience, where you can configure "apps" by pointing to their respective URL. For documents, launch GWoffice, the client for Google Docs. For calendar, launch Google Calendar.
Most Linux distros have both a number and a project name associated with them. For example, Ubuntu 10.04 LTS is known as "Lucid Lynx". The Peppermint OS team avoided this by just calling their latest version "Three" which serves as both its number and its name.
The browser is Chromium, similar to Google Chrome OS above, and uses the "DuckDuckGo" search engine. This is how the Peppermint OS folks make their money to defray the costs of this effort.
Peppermint OS claims to run in systems as little as 192MB or RAM, and only 4GB of disk space. The LiveCD ran well on both my Thinkpad T410, as well as grandma's Thinkpad R31. More importantly, when I installed on the hard drive, it ran well.
The music app "Guayadeque" that came pre-installed was awful. It couldn't play MP3 music out-of-the-box. I had to install the Codec plugins from various "ubuntu-restricted-extras" libraries. I also installed the music app "Rhythmbox", and that worked great. Time from power-on to first-note was less than 2 minutes! However, the problems with the Guayadeque gave me the impression this OS might not be ready for primetime.
I contacted grandma to ask if she has Wi-Fi in her home, and sure enough, she doesn't. Her PC upstairs is direct attached to the cable modem. So, while the Cloud suggestion was worthy of investigation, I will continue to pursue other options that do not require being connected. I certainly do not want to spend any time and effort getting Wi-Fi installed there.
(Note: The following paragraphs have been updated to clarify the performance tests involved.)
This time, IBM breaks the 1 million IOPS barrier, achieved by running a test workload consisting of a 70/30 mix of random 4K requests. That is 70 percent reads, 30 percent writes, with 4KB blocks. The throughput achieved was 3.5x times that obtained by running the identical workload on the fastest IBM storage system today (IBM System Storage SAN Volume Controller 4.3),
and an estimated EIGHT* times the performance of EMC DMX. With an average response time under 1 millisecond, this solution would be ideal for online transaction processing (OLTP) such as financial recordings or airline reservations.
(*)Note: EMC has not yet published ANY benchmarks of their EMC DMX box with SSD enterprise flash drives (EFD). However, I believe that the performance bottleneck is in their controller and not the back-end SSD or FC HDD media, so I have givenEMC the benefit of the doubt and estimated that their latest EMC DMX4 is as fast as an[IBMDS8300 Turbo] with Fibre Channel drives. If or when EMC publishes benchmarks, the marketplace can make more accurate comparisons. Your mileage may vary.
IBM used 4 TB of Solid State Disk (SSD) behind its IBM SAN Volume Controller (SVC) technology to achieve this amazing result. Not only does this represent a significantly smaller footprint, but it uses only 55 percent of the power and cooling.
The SSD drives are made by [Fusion IO] and are different than those used by EMC made by STEC.
The SVC addresses the one key problem clients face today with competitive disk systems that support SSD enterprise flash drives: choosing what data to park on those expensive drives? How do you decide which LUNs, which databases, or which files should be permanently resident on SSD? With SVC's industry-leading storage virtualization capability, you are not forced to decide. You can move data into SSD and back out again non-disruptively, as needed to meet performance requirements. This could be handy for quarter-end or year-end processing, for example.
A long time ago, perhaps in the early 1990s, I was an architect on the component known today as DFSMShsm on z/OS mainframe operationg system. One of my job responsibilities was to attend the biannual [SHARE conference to listen to the requirements of the attendees on what they would like added or changed to the DFSMS, and ask enough questions so that I can accurately present the reasoning to the rest of the architects and software designers on my team. One person requested that the DFSMShsm RELEASE HARDCOPY should release "all" the hardcopy. This command sends all the activity logs to the designated SYSOUT printer. I asked what he meant by "all", and the entire audience of 120 some attendees nearly fell on the floor laughing. He complained that some clever programmer wrote code to test if the activity log contained only "Starting" and "Ending" message, but no error messages, and skip those from being sent to SYSOUT. I explained that this was done to save paper, good for the environment, and so on. Again, howls of laughter. Most customers reroute the SYSOUT from DFSMS from a physical printer to a logical one that saves the logs as data sets, with date and time stamps, so having any "skipped" leaves gaps in the sequence. The client wanted a complete set of data sets for his records. Fair enough.
When I returned to Tucson, I presented the list of requests, and the immediate reaction when I presented the one above was, "What did he mean by ALL? Doesn't it release ALL of the logs already?" I then had to recap our entire dialogue, and then it all made sense to the rest of the team. At the following SHARE conference six months later, I was presented with my own official "All" tee-shirt that listed, and I am not kidding, some 33 definitions for the word "all", in small font covering the front of the shirt.
I am reminded of this story because of the challenges explaining complicated IT concepts using the English language which is so full of overloaded words that have multiple meanings. Take for example the word "protect". What does it mean when a client asks for a solution or system to "protect my data" or "protect my information". Let's take a look at three different meanings:
The first meaning is to protect the integrity of the data from within, especially from executives or accountants that might want to "fudge the numbers" to make quarterly results look better than they are, or to "change the terms of the contract" after agreements have been signed. Clients need to make sure that the people authorized to read/write data can be trusted to do so, and to store data in Non-Erasable, Non-Rewriteable (NENR) protected storage for added confidence. NENR storage includes Write-Once, Read-Many (WORM) tape and optical media, disk and disk-and-tape blended solutions such as the IBM Grid Medical Archive Solution (GMAS) and IBM Information Archive integrated system.
The second meaning is to protect access from without, especially hackers or other criminals that might want to gather personally-identifiably information (PII) such as social security numbers, health records, or credit card numbers and use these for identity theft. This is why it is so important to encrypt your data. As I mentioned in my post [Eliminating Technology Trade-Offs], IBM supports hardware-based encryption FDE drives in its IBM System Storage DS8000 and DS5000 series. These FDE drives have an AES-128 bit encryption built-in to perform the encryption in real-time. Neither HDS or EMC support these drives (yet). Fellow blogger Hu Yoshida (HDS) indicates that their USP-V has implemented data-at-rest in their array differently, using backend directors instead. I am told EMC relies on the consumption of CPU-cycles on the host servers to perform software-based encryption, either as MIPS consumed on the mainframe, or using their Powerpath multi-pathing driver on distributed systems.
There is also concern about internal employees have the right "need-to-know" of various research projects or upcoming acquisitions. On SANs, this is normally handled with zoning, and on NAS with appropriate group/owner bits and access control lists. That's fine for LUNs and files, but what about databases? IBM's DB2 offers Label-Based Access Control [LBAC] that provides a finer level of granularity, down to the row or column level. For example, if a hospital database contained patient information, the doctors and nurses would not see the columns containing credit card details, the accountants would not see the columnts containing healthcare details, and the individual patients, if they had any access at all, would only be able to access the rows related to their own records, and possibly the records of their children or other family members.
The third meaning is to protect against the unexpected. There are lots of ways to lose data: physical failure, theft or even incorrect application logic. Whatever the way, you can protect against this by having multiple copies of the data. You can either have multiple copies of the data in its entirety, or use RAID or similar encoding scheme to store parts of the data in multiple separate locations. For example, with RAID-5 rank containing 6+P+S configuration, you would have six parts of data and one part parity code scattered across seven drives. If you lost one of the disk drives, the data can be rebuilt from the remaining portions and written to the spare disk set aside for this purpose.
But what if the drive is stolen? Someone can walk up to a disk system, snap out the hot-swappable drive, and walk off with it. Since it contains only part of the data, the thief would not have the entire copy of the data, so no reason to encrypt it, right? Wrong! Even with part of the data, people can get enough information to cause your company or customers harm, lose business, or otherwise get you in hot water. Encryption of the data at rest can help protect against unauthorized access to the data, even in the case when the data is scattered in this manner across multiple drives.
To protect against site-wide loss, such as from a natural disaster, fire, flood, earthquake and so on, you might consider having data replicated to remote locations. For example, IBM's DS8000 offers two-site and three-site mirroring. Two-site options include Metro Mirror (synchronous) and Global Mirror (asynchronous). The three-site is cascaded Metro/Global Mirror with the second site nearby (within 300km) and the third site far away. For example, you can have two copies of your data at site 1, a third copy at nearby site 2, and two more copies at site 3. Five copies of data in three locations. IBM DS8000 can send this data over from one box to another with only a single round trip (sending the data out, and getting an acknowledgment back). By comparison, EMC SRDF/S (synchronous) takes one or two trips depending on blocksize, for example blocks larger than 32KB require two trips, and EMC SRDF/A (asynchronous) always takes two trips. This is important because for many companies, disk is cheap but long-distance bandwidth is quite expensive. Having five copies in three locations could be less expensive than four copies in four locations.
Fellow blogger BarryB (EMC Storage Anarchist) felt I was unfair pointing out that their EMC Atmos GeoProtect feature only protects against "unexpected loss" and does not eliminate the need for encryption or appropriate access control lists to protect against "unauthorized access" or "unethical tampering".
(It appears I stepped too far on to ChuckH's lawn, as his Rottweiler BarryB came out barking, both in the [comments on my own blog post], as well as his latest titled [IBM dumbs down IBM marketing (again)]. Before I get another rash of comments, I want to emphasize this is a metaphor only, and that I am not accusing BarryB of having any canine DNA running through his veins, nor that Chuck Hollis has a lawn.)
As far as I know, the EMC Atmos does not support FDE disks that do this encryption for you, so you might need to find another way to encrypt the data and set up the appropriate access control lists. I agree with BarryB that "erasure codes" have been around for a while and that there is nothing unsafe about using them in this manner. All forms of RAID-5, RAID-6 and even RAID-X on the IBM XIV storage system can be considered a form of such encoding as well. As for the amount of long-distance bandwidth that Atmos GeoProtect would consume to provide this protection against loss, you might question any cost savings from this space-efficient solution. As always, you should consider both space and bandwidth costs in your total cost of ownership calculations.
Of course, if saving money is your main concern, you should consider tape, which can be ten to twenty times cheaper than disk, affording you to keep a dozen or more copies, in as many time zones, at substantially lower cost. These can be encrypted and written to WORM media for even more thorough protection.
Well it's Tuesday again, and you know what that means.. IBM announcements! Today, IBM announces that next Monday marks the 60th anniversary of first commercial digital tape storage system! I am on the East coast this week visiting clients, but plan to be back in Tucson in time for the cake and fireworks next Monday.
1925 - masking tape (which 3M sold under its newly announced Scotch® brand)
1930 - clear cellulose-based tape (today, when people say Scotch tape, they usually are referring to the cellulose version)
1935 - Allgemeine Elektrizitatsgesellschaft (AEG) presents Magnetophon K1, audio recording on analog tape
1942 - Duct tape
1947 - Bing Crosby adopts audio recording for his radio program. This eliminated him doing the same program live twice per day, perhaps the first example of using technology for "deduplication".
According to the IBM Archives the [IBM 726 tape drive was formally announced May 21, 1952]. It was the size of a refrigerator, and the tape reel was the size of a large pizza. The next time you pull a frozen pizza from your fridge, you can remember this month's celebration!
When I first joined IBM in 1986, there were three kinds of IBM tape. The round reel called 3420, and the square cartridge called 3480, and the tubes that contained a wide swath of tape stored in honeycomb shelves called the [IBM 3850 Mass Storage System].
My first job at IBM was to work on DFHSM, which was specifically started in 1977 to manage the IBM 3850, and later renamed to the DFSMShsm component of the DFSMS element of the z/OS operating system. This software was instrumental in keeping disk and tape at high 80-95 percent utilization rates on mainframe servers.
While visiting a client in Detroit, the client loved their StorageTek tape automation silo, but didn't care for the StorageTek drives inside were incompatible with IBM formats. They wanted to put IBM drives into the StorageTek silos. I agreed it was a good idea, and brought this back to the attention of development. In a contentious meeting with management and engineers, I presented this feedback from the client.
Everyone in the room said IBM couldn't do that. I asked "Why not?" The software engineers I spoke to already said they could support it. With StorageTek at the brink of Chapter 11 bankruptcy, I argued that IBM drives in their tape automation would ease the transition of our mainframe customers to an all-IBM environment.
Was the reason related to business/legal concerns, or was their a hardware issue? It turned out to be a little of both. On the business side, IBM had to agree to work with StorageTek on service and support to its mutual clients in mixed environments. On the technical side, the drive had to be tilted 12 degrees to line up with the robotic hand. A few years later, the IBM silo-compatible 3592 drive was commercially available.
Rather than put StorageTek completely out of business, it had the opposite effect. Now that IBM drives can be put in StorageTek libraries, everyone wanted one, basically bringing StorageTek back to life. This forced IBM to offer its own tape automation libraries.
In 1993, I filed my first patent. It was for the RECYCLE function in DFHSM to consolidate valid data from partial tapes to fresh new tapes. Before my patent, the RECYCLE function selected tapes alphabetically, by volume serial (VOLSER). My patent evaluated all tapes based on how full they were, and sorted them least-full to most-full, to maximize the return of cartridges.
Different tape cartridges can hold different amounts of data, especially with different formats on the same media type, with or without compression, so calculating the percentage full turned out to be a tricky algorithm that continues to be used in mainframe environments today.
The patent was popular for cross-licensing, and IBM has since filed additional patents for this invention in other countries to further increase its license revenue for intellectual property.
In 1997, IBM launched the IBM 3494 Virtual Tape Server (VTS), the first virtual tape storage device, blending disk and tape to optimal effect. This was based off the IBM 3850 Mass Storage Systems, which was the first virtual disk system, that used 3380 disk and tape to emulate the older 3350 disk systems.
In the VTS, tape volume images would be emulated as files on a disk system, then later moved to physical tape. We would call the disk the "Tape Volume Cache", and use caching algorithms to decide how long to keep data in cache, versus destage to tape. However, there were only a few tape drives, and sometimes when the VTS was busy, there were no tape drives available to destage the older images, and the cache would fill up.
I had already solved this problem in DFHSM, with a function called pre-migration. The idea was to pre-emptively copy data to tape, but leave it also on disk, so that when it needed to be destaged, all we had to do was delete the disk copy and activate the tape copy. We patented using this idea for the VTS, and it is still used in the successor models of IBM Sysem Storage TS7740 virtual tape libraries today.
Today, tape continues to be the least expensive storage medium, about 15 to 25 times less expensive, dollar-per-GB, than disk technologies. A dollar of today's LTO-5 tape can hold 22 days worth of MP3 music at 192 Kbps recording. A full TS1140 tape cartridge can hold 2 million copies of the book "War and Peace".
(If you have not read the book, Woody Allen took a speed reading course and read the entire novel in just 20 minutes. He summed up the novel in three words: "It involves Russia." By comparison, in the same 20 minutes, at 650MB/sec, the TS1140 drive can read this novel over and over 390,000 times.)
If you have your own "war stories" about tape, I would love to hear them, please consider posting a comment below.
Five years ago, I sprayed coffee all over my screen from something I read on a blog post from fellow blogger Hu Yoshida from HDS. You can read what cased my reaction in my now infamous post [Hu Yoshida should know better]. Subsequently, over the years, I have disagreed with Hu on a variety of of topics, as documented in my 2010 blog post [Hu Yoshida Does It Again].
(Apparently, I am not alone, as the process of spraying one's coffee onto one's computer screen while reading other blog posts has been referred to as "Pulling a Tony" or "Doing a Tony" by other bloggers!)
Fortunately, my IBM colleague David Sacks doesn't drink coffee. Last month, David noticed that Hu had posted a graph in a recent blog entry titled [Additional Storage Performance Efficiencies for Mainframes], comparing the performance of HDS's Virtual Storage Platform (VSP) to IBM's DS8000.
For those not familiar with disk performance graphs, flatter is better, lower response time and larger IOPS are always desired. This graph implies that the HDS disk system is astonishingly faster than IBM's DS8000 series disk system. Certainly, the HDS VSP qualifies as a member of the elite [Super High-End club] with impressive SPC benchmark numbers, and is generally recognized as a device that works in IBM mainframe environments. But this new comparison graph is just ridiculous!
(Note: While SPC benchmarks are useful for making purchase decisions, different disk systems respond differently to different workloads. As the former lead architect of DFSMS for z/OS, I am often brought in to consult on mainframe performance issues in complex situations. Several times, we have fixed performance problems for our mainframe clients by replacing their HDS systems with IBM DS8000 series!)
Since Hu's blog entry contained very little information about the performance test used to generate the graph, David submitted a comment directly to Hu's blog asking a few simple questions to help IBM and Hu's readers determine whether the test was fair. Here is David's comment as submitted:
(Disclosure: I work for IBM. This comment is my own.)
I was quite surprised by the performance shown for the IBM DS8000 in the graph in your blog. Unfortunately, you provided very little detail about the benchmark. That makes it rather difficult (to say the least) to identify factors behind the results shown and to determine whether the comparison was a fair one.
Of the little information provided, an attribute that somewhat stands out is that the test appears to be limited to a single volume at least, that's my interpretation of "LDEV: 1*3390-3"? IBM's internal tests for this kind of case show far better response time and I/Os per second than the graph you published.
Here are a few examples of details you could provide to help readers determine whether the benchmark was fair and whether the results have any relevance to their environment.
What DS8000 model was the test run on? (the DS8000 is a family of systems with generations going back 8 years. The latest and fastest model is the DS8800.)
What were the hardware and software configurations of the DS8000 and VSP systems, including the number and speed of performance-related components?
What were the I/O workload characteristics (e.g., read:write ratio and block size(s))?
What was the data capacity of each volume? (Allocated and used capacity.)
What were the cache sizes and cache hit ratios for each system? (The average I/O response times under 1.5 milliseconds for each system imply the cache hit ratios were relatively high.)
How many physical drives were volumes striped across in each system?"
Unlike my blog on IBM, HDS bloggers like Hu are allowed to reject or deny comments before they appear on his blog post. We were disappointed that HDS never posted David's comment nor responded to it. That certainly raises questions about the quality of the comparison.
So, perhaps this is yet another case of [Hitachi Math], a phrase coined by fellow blogger Barry Burke from EMC back in 2007 in reference to outlandish HDS claims. My earliest mention was in my blog post [Not letting the Wookie Win].
By the way, since the test was about z/OS Extended Address Volumes (EAV), it is worth mentioning that IBM's DS8700 and DS8800 support 3390 volume capacities up to 1 TB each, while the HDS VSP is limited to only 223 GB per volume. Larger volume capacities help support ease-of-growth and help reduce the number of volumes storage administrators need to manage; that's just one example of how the DS8000 series continues to provide the best storage system support for z/OS environments.
Personally, I am all for running both IBM and HDS boxes side-by-side and publishing the methodology, the workload characteristics, the configuration details, and the results. Sunshine is always the best disinfectant!
Am I dreaming? On his Storagezilla blog, fellow blogger Mark Twomey (EMC) brags about EMC's standard benchmark results, in his post titled [Love Life. Love CIFS.]. Here is my take:
A Full 180 degree reversal
For the past several years, EMC bloggers have argued, both in comments on this blog, and on their own blogs, that standard benchmarks are useless and should not be used to influence purchase decisions. While we all agree that "your mileage may vary", I find standard benchmarks are useful as part of an overall approach in comparing and selecting which vendors to work with, and which architectures or solution approaches to adopt, and which products or services to deploy. I am glad to see that EMC has finally joined the rest of the planet on this. I find it funny this reversal sounds a lot like their reversal from "Tape is Dead" to "What? We never said tape was dead!"
Impressive CIFS Results
The Standard Performance Evaluation Corporation (SPEC) has developed a series of NFS benchmarks, the latest, [SPECsfs2008] added support for CIFS. So, on the CIFS side, EMC's benchmarks compare favorably against previous CIFS tests from other vendors.
On the NFS side, however, EMC is still behind Avere, BlueArc, Exanet, and IBM/NetApp. For example, EMC's combination of Celerra gateways in front of V-Max disk systems resulted in 110,621 OPS with overall response time of 2.32 milliseconds. By comparison, the IBM N series N7900 (tested by NetApp under their own brand, FAS6080) was able to do 120,011 OPS with 1.95 msec response time.
Even though Sun invented the NFS protocol in the early 1980s, they take an EMC-like approach against standard benchmarks to measure it. Last year, fellow blogger Bryan Cantrill (Sun) gives his [Eulogy for a Benchmark]. I was going to make points about this, but fellow blogger Mike Eisler (NetApp) [already took care of it]. We can all learn from this. Companies that don't believe in standard benchmarks can either reverse course (as EMC has done), or continue their downhill decline until they are acquired by someone else.
(My condolences to those at Sun getting laid off. Those of you who hire on with IBM can get re-united with your former StorageTek buddies! Back then, StorageTek people left Sun in droves, knowing that Sun didn't understand the mainframe tape marketplace that StorageTek focused on. Likewise, many question how well Oracle will understand Sun's hardware business in servers and storage.)
What's in a Protocol?
Both CIFS and NFS have been around for decades, and comparisons can sometimes sound like religious debates. Traditionally, CIFS was used to share files between Windows systems, and NFS for Linux and UNIX platforms. However, Windows can also handle NFS, while Linux and UNIX systems can use CIFS. If you are using a recent level of VMware, you can use either NFS or CIFS as an alternative to Fibre Channel SAN to store your external disk VMDK files.
The Bigger Picture
There is a significant shift going on from traditional database repositories to unstructured file content. Today, as much as [80 percent of data is unstructured]. Shipments this year are expected to grow 60 percent for file-based storage, and only 15 percent for block-based storage. With the focus on private and public clouds, NAS solutions will be the battleground for 2010.
So, I am glad to see EMC starting to cite standard benchmarks. Hopefully, SPC-1 and SPC-2 benchmarks are forthcoming?
Happy Winter Solstice everyone! The Mayan calendar flipped over yesterday, and everything continued as normal.
The next date to watch out for is ... drumroll please ... April 8, 2014. This is the date Microsoft has decided to [drop support for Windows XP].
While many large corporations are actively planning to get off Windows XP, there are still many homes and individuals that are running on this platform.
When [Windows XP] was introduced in 2001, it could support systems with as little as 64MB of RAM. Nowadays, the latest versions of Windows now requires a minimum of 1GB for 32-bit systems, with 2GB or 3GB recommended.
That leaves Windows XP users on older hardware few choices:
Continue to run Windows XP, but without support (and hope for the best)
Upgrade their hardware with more RAM (and possibly more disk space) needed to run a newer level of Windows
Install a different operating system like Linux
Put the hardware in the recycle bin, and buy a new computer
Here is a personal example. A long time ago, I gave my sister a Thinkpad R31 laptop so that she could work from home. When she got a newer one, she passed this down to her daughter for doing homework. When my neice got a newer one, she passed this old laptop to her grandma.
Grandma is fairly happy with her modern PC running Windows XP. She plays all kinds of games, scans photographs, sends emails, listens to music on iTunes, and even uses Skype to talk to relatives. Her problem is that this PC is located upstairs, in her bedroom, and she wanted something portable that she could play music downstairs when she is playing cards with her friends.
"Why not use the laptop you have?" I asked. Her response: "It runs very slow. Perhaps it has a virus. Can you fix that?" I was up for the challenge, so I agreed.
(The Challenge: Update the Thinkpad R31 so that grandma can simply turn it on, launch iTunes or similar application, and just press a "play" button to listen to her music. It will be plugged in to an electrical outlet wherever she takes it, and she already has her collection of MP3 music files. My hope is to have something that is (a) simple to use, (b) starts up quickly, and (c) will not require a lot of on-going maintenance issues.)
Here are the relevant specifications of the Thinkpad R31 laptop:
The system was pre-installed with Windows XP, but was terribly down-level. I updated to Windows XP SP3 level, downloaded the latest anti-virus signatures, and installed iTunes. A full scan found no viruses. All this software takes up 14GB, leaving less than 6GB for MP3 music files.
The time it took from hitting the "Power-on" button to hearing the first note of music was over 14 minutes! Unacceptable!
If you can suggest what my next steps should be, please comment below or send me an email!
It's Tuesday, and that means more IBM announcements!
I haven't even finished blogging about all the other stuff that got announced last week, and here we are with more announcements. Since IBM's big [Pulse 2010 Conference] is next week, I thought I would cover this week's announcement on Tivoli Storage Manager (TSM) v6.2 release. Here are the highlights:
Client-Side Data Deduplication
This is sometimes referred to as "source-side" deduplication, as storage admins can get confused on which servers are clients in a TSM client-server deployment. The idea is to identify duplicates at the TSM client node, before sending to the TSM server. This is done at the block level, so even files that are similar but not identical, such as slight variations from a master copy, can benefit. The dedupe process is based on a shared index across all clients, and the TSM server, so if you have a file that is similar to a file on a different node, the duplicate blocks that are identical in both would be deduplicated.
This feature is available for both backup and archive data, and can also be useful for archives using the IBM System Storage Archive Manager (SSAM) v6.2 interface.
Simplified management of Server virtualization
TSM 6.2 improves its support of VMware guests by adding auto-discovery. Now, when you spontaneously create a new virtual machine OS guest image, you won't have to tell TSM, it will discover this automatically! TSM's legendary support of VMware Consolidated Backup (VCB) now eliminates the manual process of keeping track of guest images. TSM also added support of the Vstorage API for file level backup and recovery.
While IBM is the #1 reseller of VMware, we also support other forms of server virtualization. In this release, IBM adds support for Microsoft Hyper-V, including support using Microsoft's Volume Shadow Copy Services (VSS).
Automated Client Deployment
Do you have clients at all different levels of TSM backup-archive client code deployed all over the place? TSM v6.2 can upgrade these clients up to the latest client level automatically, using push technology, from any client running v5.4 and above. This can be scheduled so that only certain clients are upgraded at a time.
Simultaneous Background Tasks
The TSM server has many background administrative tasks:
Migration of data from one storage pool to another, based on policies, such as moving backups and archives on a disk pool over to a tape pools to make room for new incoming data.
Storage pool backup, typically data on a disk pool is copied to a tape pool to be kept off-site.
Copy active data. In TSM terminology, if you have multiple backup versions, the most recent version is called the active version, and the older versions are called inactive. TSM can copy just the active versions to a separate, smaller disk pool.
In previous releases, these were done one at a time, so it could make for a long service window. With TSM v6.2, these three tasks are now run simultaneously, in parallel, so that they all get done in less time, greatly reducing the server maintenance window, and freeing up tape drives for incoming backup and archive data. Often, the same file on a disk pool is going to be processed by two or more of these scheduled tasks, so it makes sense to read it once and do all the copies and migrations at one time while the data is in buffer memory.
Enhanced Security during Data Transmission
Previous releases of TSM offered secure in-flight transmission of data for Windows and AIX clients. This security uses Secure Socket Layer (SSL) with 256-bit AES encryption. With TSM v6.2, this feature is expanded to support Linux, HP-UX and Solaris.
Improved support for Enterprise Resource Planning (ERP) applications
I remember back when we used to call these TDPs (Tivoli Data Protectors). TSM for ERP allows backup of ERP applications, seemlessly integrating with database-specific tools like IBM DB2, Oracle RMAN, and SAP BR*Tools. This allows one-to-many and many-to-one configurations between SAP servers and TSM servers. In other words, you can have one SAP server backup to several TSM servers, or several SAP servers backup to a single TSM server. This is done by splitting up data bases into "sub-database objects", and then process each object separately. This can be extremely helpful if you have databases over 1TB in size. In the event that backing up an object fails and has to be re-started, it does not impact the backup of the other objects.
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.