Tony Pearson is a Master Inventor and Senior IT Architect for the IBM Storage product line at the
IBM Systems Client Experience Center in Tucson Arizona, and featured contributor
to IBM's developerWorks. In 2016, Tony celebrates his 30th year anniversary with IBM Storage. 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.
(Short URL for this blog: ibm.co/Pearson )
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Now an avid reader of my blog has brought this to my attention. Apparently,
EMC has been showing customers a presentation
[Accelerating Storage Transformation with VMAX and VPLEX] with false and misleading comparison claims between IBM DS8000, HDS VSP and EMC VMAX 40K disk system performance.
(FTC Disclosure: This would be a good time to remind my readers that I work for IBM and own IBM stock. I do not endorse any of the EMC or HDS products mentioned in this post, and have no financial affiliation or investments directly with either EMC nor HDS. I am basing my information solely on the presentation posted on the internet and other sources publicly available, and not on any misrepresentations from EMC speakers at the various conferences where these charts might have been shown.)
The problem with misinformation is that it is not always obvious. The EMC presentation is quite pretty and professional-looking. It is the typical slick, attention-getting, low-content, over-simplified marketing puffery you have come to expect from EMC. There are two slides in particular that I have issue with.
This first graphic implies that IBM and HDS are nearly tied in performance, but that EMC VMAX 40K has nearly triple that bandwidth. Overall the slide has very little detail. That makes it difficult to determine what exactly is being claimed and whether a fair comparison is being made.
The title claims that VMAX 40K is "#1 in High Bandwidth Apps". Only three disk systems are shown so the claim appears to be relative to only the three systems. The wording "High Bandwidth Apps" is confusing considering the cited numbers are for disk systems and no application is identified. By comparison, IBM SONAS can drive up to 105 GB/sec sequential bandwidth, nearly double what EMC claims for its VMAX 40K, so EMC is certainly not even close to #1.
Is the workload random or sequential? That is not easy to determine. The use of "GB/s" along with the large block size of 128KB implies the I/O workload is sequential, which is great for some workloads like high performance computing, technical computing and video broadcasts. Random workloads, on the other hand, are usually measured in I/Os per second (IOPS) with a block size ranging 4KB to 64KB. (I am assuming the 128K blocks refers to 128KB block size, and not reading the same block of cache 128,000 times.)
The slide states "Maximum Sustainable RRH Bandwidth 128K Blocks". The acronym "RRH" is not defined; but I suspect this refers to "random read hits". For random workloads, 100 percent random read hits from cache represents one corner of the infamous "four corners" test. Real-world workloads have a mix of reads and writes, and a mix of cache hits and cache misses. It is also unclear whether the hits are from standard data cache or from internal buffers in adapters (perhaps accessing the same blocks repeatedly) or something else. So is this really for a random workload, or a sequential workload?
(The term "Hitachi Math" was coined by an EMC blogger precisely to slam Hitachi Data Systems for their blatant use of four-corners results, claiming that spouting ridiculously large, but equally unrealistic, 100 percent random read hit results don't provide any useful information. I agree. There are much better industry-standard benchmarks available, such as SPC-1 for random workloads, SPC-2 for sequential workloads, and even benchmarks for specific applications, that represent real-world IT environments. To shame HDS for their use of four-corners results, only for EMC themselves to use similar figures in their own presentation is truly hypocritical of them!)
The IBM system is identified as "DS8000". DS8000 is a generic family name that applies to multiple generations of systems first introduced in 2004. The specific model is not identified, but that is critical information. Is this a first generation DS8100, or the latest DS8800, or something in between?
The slide says "Full System Configs", but that is not defined and configuration details are not identified. Configuration details, also critical information in assessing system performance capabilities, are not specified. If the EMC box costs seven times more than IBM or HDS, would you really buy it to get 3x more performance? Is the EMC packed with the maximum amount of SSD? Were there any SSD in the IBM or HDS boxes to match?
The source of the claimed IBM DS8000 performance numbers is not identified. Did they run their own tests? While I cannot tell, the VMAX may have been configured with 64 Fibre Channel 8Gbps host connections. In that case each channel is theoretically capable of supporting about 800 MB/s at 100% channel utilization. Multiplying 64 x 800MB/s = 51.2GB/s, so did EMC just do the performance comparison on the back of a napkin, assuming there are no other bottlenecks in the system? Even then, I would not round up 51.2 to 52!
Response times were not identified. For random I/Os, response time is a very important metric. It is possible that the Symmetrix was operating with some resources at 100% utilization to get the highest GB/s result, but that would likely make I/O response times unacceptable for real-world random I/O workloads.
IBM and HDS have both published Storage Performance Council [SPC] industry-standard performance benchmarks. EMC has not published any SPC benchmarks for VMAX systems. If EMC is interested in providing customers with audited, detailed performance information along with detailed configuration information, all based on benchmarks designed to represent real-world workloads, EMC can always publish SPC benchmark results as IBM and other vendors have done. In past blog fights, EMC resorts to the excuse that SPC isn't perfect, but can they really argue that vague and unrealistic claims cited in its presentation are better?
The second graphic is so absurd, you would think it came directly from Larry Ellison at an Oracle OpenWorld keynote session. EMC is comparing a configuration with VMAX 40K plus an EMC VFCache host-side flash memory cache card to a configuration with an IBM and HDS disk system without host-side flash memory cache also configured. The comparison is clearly apples-to-oranges. Other disk system configuration details are also omitted.
FAST VP is EMC's name for its sub-volume drive tiering feature, comparable to IBM Easy Tier and Hitachi's Dynamic Tiering. The graph implies that IBM and HDS can only achieve a modest increment improvement from their sub-volume tiering. I beg to differ. I have seen various cases where a small amount of SSD on IBM DS8000 series can drastically improve performance 200 to 400 percent.
The "DBClassify" shown on the graph is a tool run as part of an EMC professional services offering called Database Performance Tiering Assessment, makes recommendations for storing various database objects on different drive tiers based on object usage and importance. Do you really need to pay for professional services? With IBM Easy Tier, you just turn it on, and it works. No analysis required, no tools, no professional services, and no additional charge!
VFCache is an optional product from EMC that currently has no integration whatsoever with VMAX. A fair comparison would have included a host-side flash memory cache (from any vendor) when the IBM or HDS storage system was configured. Or leave it out altogether and just focus on the sub-volume tiering comparison.
Keep in mind that EMC's VFCache supports only selected x86-based hosts. IBM has published a [Statement of Direction] indicating that it will also offer this for Power systems running AIX and Linux host-side flash memory cache integrated with DS8000 Easy Tier.
I feel EMC's claims about IBM DS8000 performance are vague and misleading. EMC appears to lack the kind of technical marketing integrity that IBM strives to attain.
Since EMC is not able or willing to publish fair and meaningful performance comparisons, it is up to me to set the record straight and point out EMC's failings in this matter.
Reminder: It's not to late to register for my Webcast "Solving the Storage Capacity Crisis" on Tuesday, September 25. See my blog post [Upcoming events in September] to register!
Those that prefer to work with one-stop shopping of an IT Supermarket, with companies like IBM, HP and Dell who offer a complete set of servers, storage, switches, software and services, what we call "The Five S's".
Those that perfer shopping for components at individual specialty shops, like butchers, bakers, and candlestick makers, hoping that this singular focus means the products are best-of-breed in the market. Companies like HDS for disk, Quantum for tape, and Symantec for software come to mind.
My how the IT landscape for vendors has evolved in just the past five years! Cisco starts to sell servers, and enters a "mini-mall" alliance with EMC and VMware to offer vBlock integrated stack of server, storage and switches with VMware as the software hypervisor. For those not familiar with the concept of mini-malls, these are typically rows of specialty shops. A shopper can park their car once, and do all their shopping from the various shops in the mini-mall. Not quite "one-stop" shopping of a supermarket, but tries to address the same need.
("Who do I call when it breaks?" -- The three companies formed a puppet company, the Virtual Computing Environment company, or VCE, to help answer that question!)
Among the many things IBM has learned in its 100+ years of experience, it is that clients want choices. Cisco figured this out also, and partnered with NetApp to offer the aptly-named FlexPod reference architecture. In effect, Cisco has two boyfriends, when she is with EMC, it is called a Vblock, and when she is with NetApp, it is called a FlexPod. I was lucky enough to find this graphic to help explain the three-way love triangle.
Did this move put a strain on the relationship between Cisco and EMC? Last month, EMC announced VSPEX, a FlexPod-like approach that provides a choice of servers, and some leeway for resellers to make choices to fit client needs better. Why limit yourself to Cisco servers, when IBM and HP servers are better? Is this an admission that Vblock has failed, and that VSPEX is the new way of doing things? No, I suspect it is just EMC's way to strike back at both Cisco and NetApp in what many are calling the "Stack Wars". (See [The Stack Wars have Begun!], [What is the Enterprise Stack?], or [The Fight for the Fully Virtualized Data Center] for more on this.)
(FTC Disclosure: I am both an employee and shareholder of IBM, so the U.S. Federal Trade Commission may consider this post a paid, celebrity endorsement of the IBM PureFlex system. IBM has working relationships with Cisco, NetApp, and Quantum. I was not paid to mention, nor have I any financial interest in, any of the other companies mentioned in this blog post. )
Last month, IBM announced its new PureSystems family, ushering in a [new era in computing]. I invite you all to check out the many "Paterns of Expertise" available at the [IBM PureSystems Centre]. This is like an "app store" for the data center, and what I feel truly differentiates IBM's offerings from the rest.
The trend is obvious. Clients who previously purchased from specialty shops are discovering the cost and complexity of building workable systems from piece-parts from separate vendors has proven expensive and challenging. IBM PureFlex™ systems eliminate a lot of the complexity and effort, but still offer plenty of flexibility, choice of server processor types, choice of server and storage hypervisors, and choice of various operating systems.
This week, I am in beautiful Sao Paulo, Brazil, teaching Top Gun class to IBM Business Partners and sales reps. Traditionally, we have "Tape Thursday" where we focus on our tape systems, from tape drives, to physical and virtual tape libraries. IBM is the number #1 tape vendor, and has been for the past eight years.
(The alliteration doesn't translate well here in Brazil. The Portuguese word for tape is "fita", and Thursday here is "quinta-feira", but "fita-quinta-feira" just doesn't have the same ring to it.)
In the class, we discussed how to handle common misperceptions and myths about tape. Here are a few examples:
Myth 1: Tape processing is manually intensive
In my July 2007 blog post [Times a Million], I coined the phrase "Laptop Mentality" to describe the problem most people have dealing with data center decisions. Many folks extend linearly their experiences using their PCs, workstations or laptops to apply to the data center, unable to comprehend large numbers or solutions that take advantage of the economies of scale.
For many, the only experience dealing with tape was manual. In the 1980s, we made "mix tapes" on little cassettes, and in the 1990s we recorded our favorite television shows on VHS tapes in the VCR. Today, we have playlists on flash or disk-based music players, and record TV shows on disk-based video recorders like Tivo. The conclusion is that tapes are manual, and disk are not.
Manual processing of tapes ended in 1987, with the introduction of a silo-like tape library from StorageTek. IBM quickly responded with its own IBM 3495 Tape Library Data Server in 1992. Today, clients have many tape automation choices, from the smallest IBM TS2900 Tape Autoloader that has one drive and nine cartridges, all the way to the largest IBM TS3500 multiple-library shuttle complex that can hold exabytes of data. These tape automation systems eliminate most of the manual handling of cartridges in day-to-day operations.
Myth 2: Tape media is less reliable than disk media
For any storage media to be unreliable is to return the wrong information that is different than what was originally stored. There are only two ways for this to happen: if you write a "zero" but read back a "one", or write a "one" and read a "zero". This is called a bit error. Every storage media has a "bit error rate" that is the average likelihood for some large amount of data written.
According to the latest [LTO Bit Error rates, 2012 March], today's tape expects only 1 bit error per 10E17 bits written (about 100 Petabytes). This is 10 times more reliable than Enterprise SAS disk (1 bit per 10E16), and 100 times more reliable than Enterprise-class SATA disk (1 bit per 10E15).
Tape is the media used in "black boxes" for airplanes. When an airplane crashes, the black box is retrieved and used to investigate the causes of the crash. In 1986, the Space Shuttle Challenger exploded 73 seconds after take-off. The tapes in the black box sat on the ocean floor for six weeks before being recovered. Amazingly, IBM was able to successfully restore [90 percent of the block data, and 100 percent of voice data].
Analysts are quite upset when they are quoted out of context, but in this case, Gartner never said anything closely similar to this. Nor did the other analysts that Curtis investigated for similar claims. What Garnter did say was that disk provides an attractive alternative storage media for backup which can increase the performance of the recovery process.
Back in the 1990s, Savur Rao and I developed a patent to help backup DB2 for z/OS by using the FlashCopy feature of IBM's high-end disk system. The software method to coordinate the FlashCopy snapshots with the database application and maintain multiple versions was implemented in the DFSMShsm component of DFSMS. A few years later, this was part of a set of patents IBM cross-licensed to Microsoft for them to implement a similar software for Windows called Data Protection Manager (DPM). IBM has since introduced its own version for distributed systems called IBM Tivoli FlashCopy Manager that runs not just on Windows, but also AIX, Linux, HP-UX and Solaris operating systems.
Curtis suspects the "71 percent" citation may have been propogated by an ambitious product manager of Microsoft's Data Protection Manager, back in 2006, perhaps to help drive up business to their new disk-based backup product. Certainly, Microsoft was not the only vendor to disparage tape in this manner.
A few years ago, an [EMC failure brought down the State of Virginia] due to not just a component failure it its production disk system, but then made it worse by failing to recover from the disk-based remote mirror copy. Fortunately, the data was able to be restored from tape over the next four days. If you wonder why nobody at EMC says "Tape is Dead" anymore, perhaps it is because tape saved their butts that week.
(FTC Disclosure: I work for IBM and this post can be considered a paid, celebrity endorsement for all of the IBM tape and software products mentioned on this post. I own shares of stock in both IBM and Google, and use Google's Gmail for my personal email, as well as many other Google services. While IBM, Google and Microsoft can be considered competitors to each other in some areas, IBM has working relationships with both companies on various projects. References in this post to other companies like EMC are merely to provide illustrative examples only, based on publicly available information. IBM is part of the Linear Tape Open (LTO) consortium.)
Myth 4: Vendors and Manufacturers are no longer investing in tape technology
IBM and others are still investing Research and Development (R&D) dollars to improve tape technology. What people don't realize is that much of the R&D spent on magnetic media can be applied across both disk and tape, such as IBM's development of the Giant Magnetoresistance read/write head, or [GMR] for short.
Most recently, IBM made another major advancement with tape with the introduction of the Linear Tape File Systems (LTFS). This allows greater portability to share data between users, and between companies, but treating tape cartridges much like USB memory sticks or pen drives. You can read more in my post [IBM and Fox win an Emmy for LTFS technology]!
Next month, IBM celebrates the 60th anniversary for tape. It is good to see that tape continues to be a vibrant part of the IT industry, and to IBM's storage business!
The old adage applies "You can't please everyone. Presidents can't. Prostitutes can't. Nobody can." I am reminded of that as I fielded a variety of interesting comments and emails about, of all things, my choice of order of things in recent blog posts.
Certainly, there are times when the order of things matters greatly. In my now-infamous blog post [Sock Sock Shoe Shoe], I use a scene from a popular 1970's television show to explain why compression should be done before encryption.
In my case, I put things in the order that I felt made sense to me, but not everyone agrees. Here are three recent examples:
In my blog post [Two IBMers Earn Their Retirement], I congratulated two of my colleagues on their retirement. Since their retirement happened on the same day, I decided to mention Mark Doumas first, and Jim Rymarczyk second.
However, one of my readers, who I will assume is a member of the unofficial "Jim Rymarczyk fan club", felt that I should have listed Jim first, as Jim served IBM for 44 years, and Mark only 32 years.
Really? I realize that movie stars insist on having their name listed first on the poster, but neither of these guys would be confused with George Clooney!
So, to Jim and all his fans out there, I assure you I did not mean this as a slight in any way. I have updated the post to indicate that the ordering was strictly alphabetical by last name.
In my blog post [IBM Announcements for February 2012], I presented tape products first, and disk second. Normally, I cover them alphabetically, disk first, then tape. However, I was asked to promote tape this year in preparation for the upcoming 60th anniversary of tape, so I mentioned the tape announcements first, and the disk second.
The feedback from the XIV community was swift. Many felt that I [buried the lede] in not mentioning the XIV Gen3 SSD caching first.
(Note: For those not familiar with the phrase used in journalism, 'burying the lede' refers to the failure to mention the most interesting or attention grabbing elements of a story in the first paragraph. In American news journalism, it is spelled "lede" and elsewhere it is spelled "lead". Major US dictionaries apparently accept both spellings for this phrase.)
Technically, my lead paragraph stated clearly that: "This week we have announcements for both disk and tape, but since 2012 is the 60th Diamond Anniversary for tape, I will start with tape systems first."
So, while I don't claim to be a journalist by any means, I think the lead paragraph accurately reflected that I would talk about both disk and tape products in the rest of the blog post, and if a reader didn't care to learn more about tape could bypass those sections and go directly to the section on disk instead.
I have had my head handed to me on a platter so many times here at IBM that I am considering installing a zipper around my neck. My friends in XIV land insisted that I write a secondary post about XIV Gen3 SSD caching that had no mention of tape whatsoever. One suggestion was to compare and contrast XIV Gen3 SSD caching with EMC's announcement for VFCache. The result was my blog post [IBM XIV Gen3 SSD Caching versus EMC VFCache].
What could go wrong with an apples-to-orange comparison of two different storage products sprinkled with a small amount of FUD against a major competitor?
I had two complaints on this one. First, is the order of products in my side-by-side table of comparisons. I put EMC VFCache in the left column, and IBM XIV Gen3 SSD caching in the right. I meant nothing sinister by this. Alphabetically, EMC comes before IBM, and VFCache comes before XIV. Chronologically, EMC's announcement came out on Monday, and IBM's announcement came out the following day.
(Note: The term [sinster] comes from the Latin word sinistra meaning "left hand". In the Middle Ages it was believed that when a person was writing with their left hand they were possessed by the Devil. Left-handed people were therefore considered to be evil. My poor mother was born left-handed and was forced as a child to write with her right hand to be accepted by society.)
Apparently, an unwritten convention within IBM is that comparison tables always have the newer product on the left column, followed by one or more older products to the right, or the IBM product on the left column, with one or more competitive alternatives to the right.
The second complaint came from a reader in the comments section: "... I think [what] you're doing is trying to ride EMC's release for your own marketing, did you really need to? XIV is an excellent array; adding SSD Cache to the Gen3 takes it further, Moshe would be fuming (which I think is a good thing), can you just stick to that and not ride someone else's wave?"
Both announcements relate to reducing latency of read IOPS through the use of Solid State Drives. That both companies would announce these were no surprise to any employee at either company, as both IBM and EMC have been talking about their intent to do so last year. IBM's announcement of XIV SSD Gen3 caching was certainly not in response to EMC's VFCache announcement, and I doubt EMC rushed out their VFCache announcement the day before as a pre-emptive strike against IBM's announcement of the XIV Gen3 SSD Caching feature.
(Note: I don't know her personally, but she has thousands of followers!)
There you have it. I will gladly fix false or misleading information, but I am not going to re-arrange the order of things just to please some readers, only to have other readers complain that they liked it better in the original order. As always, feel free to comment on any of this in the section below.
Have you ever noticed that sometimes two movies come out that seem eerily similar to each other, released by different studios within months or weeks of each other? My sister used to review film scripts for a living, she would read ten of them and have to pick her top three favorites, and tells me that scripts for nearly identical concepts came all the time. Here are a few of my favorite examples:
1994: [Wyatt Earp] and [Tombstone] were Westerns recounting the famed gunfight at the O.K. Corral. Tombstone, Arizona is near Tucson, and the gunfight is recreated fairly often for tourists.
1998: [Armageddon] and [Deep Impact] were a pair of disaster movies dealing with a large rock heading to destroy all life on earth. I was in Mazatlan, Mexico to see the latter, dubbed in Spanish as "Impacto Profundo".
1998: [A Bug's Life] and [Antz] were computer-animated tales of the struggle of one individual ant in an ant colony.
2000: [Mission to Mars] and [Red Planet] were sci-fi pics exploring what a manned mission to our neighboring planet might entail.
This is different than copy-cat movies that are re-made or re-imagined many years later based on the previous successes of an original. Ever since my blog post [VPLEX: EMC's Latest Wheel is Round] in 2010 comparing EMC's copy-cat product that came our seven years after IBM's SAN Volume Controller (SVC), I've noticed EMC doesn't talk about VPLEX that much anymore.
This week, IBM announced [XIV Gen3 Solid-State Drive support] and our friends over at EMC announced [VFCache SSD-based PCIe cards]. Neither of these should be a surprise to anyone who follows the IT industry, as IBM had announced its XIV Gen3 as "SSD-Ready" last year specifically for this purpose, and EMC has been touting its "Project Lightning" since last May.
Fellow blogger Chuck Hollis from EMC has a blog post [VFCache means Very Fast Cache indeed] that provides additional detail. Chuck claims the VFCache is faster than popular [Fusion-IO PCIe cards] available for IBM servers. I haven't seen the performance spec sheets, but typically SSD is four to five times slower than the DRAM cache used in the XIV Gen3. The VFCache's SSD is probably similar in performance to the SSD supported in the IBM XIV Gen3, DS8000, DS5000, SVC, N series, and Storwize V7000 disk systems.
Nonetheless, I've been asked my opinions on the comparison between these two announcements, as they both deal with improving application performance through the use of Solid-State Drives as an added layer of read cache.
(FTC Disclosure: I am both a full-time employee and stockholder of the IBM Corporation. The U.S. Federal Trade Commission may consider this blog post as a paid celebrity endorsement of IBM servers and storage systems. This blog post is based on my interpretation and opinions of publicly-available information, as I have no hands-on access to any of these third-party PCIe cards. I have no financial interest in EMC, Fusion-IO, Texas Memory Systems, or any other third party vendor of PCIe cards designed to fit inside IBM servers, and I have not been paid by anyone to mention their name, brands or products on this blog post.)
The solutions are different in that IBM XIV Gen3 the SSD is "storage-side" in the external storage device, and EMC VFCache is "server-side" as a PCI Express [PCIe] card. Aside from that, both implement SSD as an additional read cache layer in front of spinning disk to boost performance. Neither is an industry first, as IBM has offered server-side SSD since 2007, and IBM and EMC have offered storage-side SSD in many of their other external storage devices. The use of SSD as read cache has already been available in IBM N series using [Performance Accelerator Module (PAM)] cards.
IBM has offered cooperative caching synergy between its servers and its storage arrays for some time now. The predecessor to today's POWER7-based were the iSeries i5 servers that used PCI-X IOP cards with cache to connect i5/OS applications to IBM's external disk and tape systems. To compete in this space, EMC created their own PCI-X cards to attach their own disk systems. In 2006, IBM did the right thing for our clients and fostered competition by entering in a [Landmark agreement] with EMC to [license the i5 interfaces]. Today, VIOS on IBM POWER systems allows a much broader choice of disk options for IBM i clients, including the IBM SVC, Storwize V7000 and XIV storage systems.
Can a little SSD really help performance? Yes! An IBM client running a [DB2 Universal Database] cluster across eight System x servers was able to replace an 800-drive EMC Symmetrix by putting eight SSD Fusion-IO cards in each server, for a total of 64 Solid-State drives, saving money and improving performance. DB2 has the Data Partitioning Feature that has multi-system DB2 configurations using a Grid-like architecture similar to how XIV is designed. Most IBM System x and BladeCenter servers support internal SSD storage options, and many offer PCIe slots for third-party SSD cards. Sadly, you can't do this with a VFCache card, since you can have only one VFCache card in each server, the data is unprotected, and only for ephemeral data like transaction logs or other temporary data. With multiple Fusion-IO cards in an IBM server, you can configure a RAID rank across the SSD, and use it for persistent storage like DB2 databases.
Here then is my side-by-side comparison:
IBM XIV Gen3 SSD Caching
Selected x86-based models of Cisco UCS, Dell PowerEdge, HP ProLiant DL, and IBM xSeries and System x servers
All of these, plus any other blade or rack-optimized server currently supported by XIV Gen3, including Oracle SPARC, HP Titanium, IBM POWER systems, and even IBM System z mainframes running Linux
Operating System support
Linux RHEL 5.6 and 5.7, VMware vSphere 4.1 and 5.0, and Windows 2008 x64 and R2.
All of these, plus all the other operating systems supported by XIV Gen3, including AIX, IBM i, Solaris, HP-UX, and Mac OS X
FCP and iSCSI
Vendor-supplied driver required on the server
Yes, the VFCache driver must be installed to use this feature.
No, IBM XIV Gen3 uses native OS-based multi-pathing drivers.
External disk storage systems required
None, it appears the VFCache has no direct interaction with the back-end disk array, so in theory the benefits are the same whether you use this VFCache card in front of EMC storage or IBM storage
XIV Gen3 is required, as the SSD slots are not available on older models of IBM XIV.
Shared disk support
No, VFCache has to be disabled and removed for vMotion to take place.
Yes! XIV Gen3 SSD caching shared disk supports VMware vMotion and Live Partition Mobility.
Support for multiple servers
An advantage of the XIV Gen3 SSD caching approach is that the cache can be dynamically allocated to the busiest data from any server or servers.
Support for active/active server clusters
Aware of changes made to back-end disk
No, it appears the VFCache has no direct interaction with the back-end disk array, so any changes to the data on the box itself are not communicated back to the VFCache card itself to invalidate the cache contents.
None identified. However, VFCache only caches blocks 64KB or smaller, so any sequential processing with larger blocks will bypass the VFCache.
Yes! XIV algorithms detect sequential access and avoid polluting the SSD with these blocks of data.
Number of SSD supported
One, which seems odd as IBM supports multiple Fusion-IO cards for its servers. However, this is not really a single point of failure (SPOF) as an application experiencing a VFCache failure merely drops down to external disk array speed, no data is lost since it is only read cache.
6 to 15 (one per XIV module) for high availability.
Pin data in SSD cache
Yes, using split-card mode, you can designate a portion of the 300GB to serve as Direct-attached storage (DAS). All data written to the DAS portion will be kept in SSD. However, since only one card is supported per server and the data is unprotected, this should only be used for ephemeral data like logs and temp files.
No, there is no option to designate an XIV Gen3 volume to be SSD-only. Consider using Fusion-IO PCIe card as a DAS alternative, or another IBM storage system for that requirement.
Pre-sales Estimating tools
Yes! CDF and Disk Magic tools are available to help cost-justify the purchase of SSD based on workload performance analysis.
IBM has the advantage that it designs and manufactures both servers and storage, and can design optimal solutions for our clients in that regard.
I took over a hundred pictures at this event. Here are a few of my favorites from Monday and Tuesday.
The IBM Booth #1111 Moscone South
I spent most of my time at the booth in the exhibition area. It was a huge booth, covering various software offerings in the front, and servers and storage systems in the back. Here I am next to the "IBM Watson" simulator, allowing people to play Jeopardy! game against Watson.
In the front was "EoS" which stands for "Exchanging Opinions for Solutions" -- an interactive screen developed by Somnio that allows people to enter questions and opinions and get crowd-sourced answers from people following the Twitter stream. The EoS was connected to the [IBM Mobile App] so people could follow the conversation.
IBM Customer Appreciation Events
On Monday evening we had some customer appreciation events. First was for IBM customers of "JD Edwards", which runs on "IBM i" operating system on POWER servers. This was an elegant affair at the [Weinstein Gallery] surrounded by works of art by Pablo Picasso and Marc Chagall. One customer expressed concern that Oracle would functionally stabilize JD Edwards "World" software and force everyone to move over to "Enterprise One". I told him that I had seen the roadmap for "World" and there are three healthy releases planned for its future. He should have nothing to worry about. IBM and Oracle will work together to make sure our mutual customers get the solutions they need.
Later, we went to the "Infusion" bar for another "IBM appreciation" event with a live band. Here's a Polaroid photo taken of me in the crowd.
Titan Gala Award Reception
On Tuesday night, Oracle gave out awards in 29 categories. IBM won three this year. I took a photo with the ladies from Beach Blanket Babylon, and a mermaid! Joining me to celebrate the awards were IBMers Carolann Kohler, Boyd Fenton, Sue Haad, and Susan Adomovich.
This is my first time attending Oracle OpenWorld, so naively I asked why there were only 29 categories and not an even 30. The IBMers joked that the 30th might as well have been "Best Server/Storage Platform for Integer Math" which Larry Ellison conceded that IBM's POWER 795 server wins over Oracle's new SPARC T4 Supercluster. As Larry said during his keynote "We still have some work to do to beat IBM!"
The event was held at the San Francisco City Hall, I got to walk on the red carpet, with lavish food and drink. I was even given a hand-rolled cigar! Thank you Oracle! We are proud to be your "Diamond Partner" helping our mutual customers get the most out of our solutions.
The "Booth Babes" Controversy
At the EMC booth, these three lovely ladies, Jennifer, Tamara and Manuela, were just a few of the dozen so-called booth babes EMC hired from a local agency. Attendees with technical questions were directed to the EMC guys in the back of the booth, behind the wall.
IBM stopped using "booth babes" a long while ago. At IBM Booth #1111, we had a healthy balance of real men and women executives, technical experts, and support staff at the IBM booth.
A guy from EMC came over to our booth later to explain that EMC is at two other events this same week, and their technical staff is spread thin. EMC is a small company, and skilled technical people are in short supply. We get it. Not every IT vendor has an army of experts in every category like IBM.
I want to thank the IBM-Oracle Alliance team, especially Nancy Spurry and Carolann Kohler for having me involved in these events.
Monday morning of the [Oracle OpenWorld 2011] conference had Joe Tucci, CEO of EMC, present the keynote. Joe indicated that I.T. stands for "Industry in Transition". He had a chart that showed the history of IT, from the mainframe and mini-computer, to the PC and client/server era, and now to the Cloud era. He called these "waves of disruption". The catalysts for change are a "Budge Dilemma", "Information Deluge" and "Cyber Security". The keynote was very similar to what EMC presented at [VMworld] conference earlier this summer.
"We have failed our customers. Over the past 10 years, they spend 73% to maintain their existing systems, and only 27% for new."
--- Joe Tucci, EMC
While many people equate "EMC" and "Failure", I believe Joe was referring not just to his own company, but most of the other IT vendors as well. Analysts predict that from January 1, 2010 to December 31, 2019, the world of stored data will grow from 0.9 ZB to 35.2 ZB, which represents a 44x increase. During that same time, IT staff is only expected to grow 50 percent. A staggering 90 percent of this data will be unstructured (non-database) content. Meanwhile, the average company gets cyber-attacked 300 times per week.
The answer is Cloud Computing. A few years ago, EMC was trying to get people to go "private cloud" route instead of "public cloud", they now have a more realistic "hybrid cloud" approach similar to IBM. Of the clients that EMC works with, 35 percent are implementing some form of cloud, and another 30 percent are planning to. The tenents of Hybrid Cloud are "Efficiency", "Control" and "Choice" which equals "Agility".
Joe also mentioned that there is now a new "layering" for IT. Instead of storage, switches and servers, we have a cloud platform of shared resources, mobile devices like smartphones and tablets, and management.
Joe feels there is a massive opportunity where Cloud meets Big Data. A cute video showed a driver wearing a motorcycle helmet so you can't see his face get into an under-powered car with "VNXe" on the license plate. He punches in "Cloud and Big Data" into the GPS navigation system, and starts out on city streets. Then the car transforms to an under-utilized family sedan "VNX" on a highway in the middle of the desert, then transforms to an over-priced sports car labeled "VMAX" as it climbs into the mountains surrounded by fog. The video borrowed the "CARS" theme from the videos IBM developed for its 2008 launch of "Information Infrastructure" initiative.
EMC's Pat Gelsinger (CTO) and fellow blogger Chad Sakac did some demos of VMware vCenter. They called the VMware vSphere "the Datacenter-wide OS" indicating that EMC storage has 75 points of integration with their "partner" (VMware is majority-owned by EMC, so I am not sure if partner is the right term). If you don't count Itanium, SPARC, POWER and IBM Syste z architectures, VMware enjoys over 80 percent marketshare for server virtualization.
(Full disclosure: IBM is the leading reseller of VMware.)
Pat claims that 40 percent of Oracle Apps at EMC run VMware. For the longest time, Oracle refused support its apps on VMware, but they relaxed this restrictive policy back in 2009. Today, nearly 25 percent of Oracle Apps run virtualized. EMC claims that they can support 5 million VMs on a single VMAX, and can generate 1 million IOPS from a single VMware ESX host.
Chad did a demo of vFabric which allows a vCenter plug-in to kick up Database instances of OracleDB, MySQL, Hadoop, PostgreSQL, and GreenPlum (GreenPlum is EMC's version of open-source PostgreSQL).
Chad showed that VMware vMition could move workloads from servers without solid-state, to servers that are flash-enabled. Lightweight workloads can be moved from DAS-enabled servers to compute-enabled storage devices like their EMC Isilon. (EMC acquired Isilon to offer their me-too version of IBM's Scale-Out NAS [SONAS] product.) EMC announced their first "Solid-State on a PCIe card" from their Project Lightning initiative. These are 320 GB capacity, so they sounded like a me-too versino of IBM's [Fusion-io IOdrive] cards that IBM has had available for quite some time now.
Next, Pat and Chad talked about Big Data. The world is transforming from a manual scale-up model to an automated scale-out architecture. Moving from "islands" to "pools". They used a cute example of Car Insurance. Business Analytics were able to review a safe drivers record, including the driver's Facebook and Twitter activity, and give him a discount, and then review the bad driving habits of another driver, and raise the bad driver's rates.
EMC announced their "GreenPlum Analytics Platform" (GAP?). I often tell people that if you want to predict what EMC will announce next, just look at what IBM announced 18 months ago. This new platform sounds like their me-too version of IBM's [Smart Analytics System].
After EMC, Judith Sim from Oracle introduced the Ed Lee, the Mayor of San Francisco which was just named the "Greenest city in North America". He thanked the audience for contributing an estimated $100 million USD to his local economy. Also, he was happy that by eliminating paper-based handouts and conference materials, the audience saved 1,636 trees.
Mark Hurd, formerly CEO of HP, and now president of Oracle, gave some highlights of 2011, and what Oracle's strategy is going forward. He said that Oracle plans to provide complete stacks, complete choice, and have each component of the stack be best-of-breed. In 2011, Oracle introduced the new MySQL 5.5 database, Java 7 programming language, and the Solaris 11 operating system with ZFS file system. Oracle spent $4 Billion in R&D, and gained 20 percent growth in software licenses, which gave them 33 percent growth fiscally for 2011 year. Oracle acquired Larry Ellison's [Pillar Data] storage company. Oracle also launched a [Database Appliance].
Thomas Kurian, another Oracle executive, finished the keynote session. He started with yet another chart showing the historical transition from Mainframe to Tablet. He indicated that leading-edge OracleDB and their Fusion middleware combined with industry standard hardware provides 5-30x faster queries, 4-10x less disk space, and simplifies the data center footprint. Their Exadata provides what he likes to call "Hierarchical Storage Management" between DRAM, Flash Solid-State, and spinning disk.
(Note: I started my career at IBM in 1986 working on a product called DFHSM, the Data Facility Hierarchical Storage Manager! It is now a vibrant component of DFSMS, part of IBM's z/OS mainframe operating system.)
ps this new announcement is to address that deficiency.
Finally, Oracle announced their "Exadata Storage Expansion Rack". Many people realized that the Exadata was under-provisioned for storage, which explains why they have only sold a few thousand of them, so perha
If you are attending Oracle OpenWorld, here are sessions for Tuesday that IBM is featuring. Note the first two are Solution Spotlight sessions at the IBM Booth #1111 where I will be most of the time.
Securing Heterogeneous Database Infrastructures: A Comprehensive Approach
10/04/11, 9:45 a.m. -- 10:15 a.m., Solution Spotlight, Booth #1111 Moscone South
Presenter: Al Cooley, Director, IBM InfoSphere Guardium
IBM Business Analystics for Oracle Solutions
10/04/11, 2:15 p.m. -- 2:45 p.m., Solution Spotlight, Booth #1111 Moscone South
Presenter: John Strazdins, ERP Strategy Executive
Consolidated Global View of Your Customer with One Global Billing System
10/04/11, 3:30 p.m. -- 4:30 p.m., OpenWorld session #23650
Presenter: John Waterman, IBM
Enterprise billing system technologies are emerging to assist with global customer views and other challenges banks struggle with today. In this session, Citi discusses its challenges and successes in implementing a global billing system.
Upgrading Your Siebel CRM with Reduced Risk and Lowered Cost: Customer Successes
10/04/11, 3:30 p.m. -- 4:30 p.m., OpenWorld session #18222
Presenters: Arnaud Wingelaar, IBM; Geetha Sundaram; Agnes Zhang, Oracle
Hear customer success stories about upgrading Siebel CRM. Learn best practices on upgrading with lowered cost, or achieving a high-availability upgrade with zero downtime and reduced risk.
Over on the Tivoli Storage Blog, there is an exchange over the concept of a "Storage Hypervisor". This started with fellow IBMer Ron Riffe's blog post [Enabling Private IT for Storage Cloud -- Part I], with a promise to provide parts 2 and 3 in the next few weeks. Here's an excerpt:
"Storage resources are virtualized. Do you remember back when applications ran on machines that really were physical servers (all that “physical” stuff that kept everything in one place and slowed all your processes down)? Most folks are rapidly putting those days behind them.
In August, Gartner published a paper [Use Heterogeneous Storage Virtualization as a Bridge to the Cloud] that observed “Heterogeneous storage virtualization devices can consolidate a diverse storage infrastructure around a common access, management and provisioning point, and offer a bridge from traditional storage infrastructures to a private cloud storage environment” (there’s that “cloud” language). So, if I’m going to use a storage hypervisor as a first step toward cloud enabling my private storage environment, what differences should I expect? (good question, we get that one all the time!)
The basic idea behind hypervisors (server or storage) is that they allow you to gather up physical resources into a pool, and then consume virtual slices of that pool until it’s all gone (this is how you get the really high utilization). The kicker comes from being able to non-disruptively move those slices around. In the case of a storage hypervisor, you can move a slice (or virtual volume) from tier to tier, from vendor to vendor, and now, from site to site all while the applications are online and accessing the data. This opens up all kinds of use cases that have been described as “cloud”. One of the coolest is inter-site application migration.
A good storage hypervisor helps you be smart.
Application owners come to you for storage capacity because you’re responsible for the storage at your company. In the old days, if they requested 500GB of capacity, you allocated 500GB off of some tier-1 physical array – and there it sat. But then you discovered storage hypervisors! Now you tell that application owner he has 500GB of capacity… What he really has is a 500GB virtual volume that is thin provisioned, compressed, and backed by lower-tier disks. When he has a few data blocks that get really hot, the storage hypervisor dynamically moves just those blocks to higher tier storage like SSD’s. His virtual disk can be accessed anywhere across vendors, tiers and even datacenters. And in the background you have changed the vendor storage he is actually sitting on twice because you found a better supplier. But he doesn’t know any of this because he only sees the 500GB virtual volume you gave him. It’s 'in the cloud'."
"Let’s start with a quick walk down memory lane. Do you remember what your data protection environment looked like before virtualization? There was a server with an operating system and an application… and that thing had a backup agent on it to capture backup copies and send them someplace (most likely over an IP network) for safe keeping. It worked, but it took a lot of time to deploy and maintain all the agents, a lot of bandwidth to transmit the data, and a lot of disk or tapes to store it all. The topic of data protection has modernized quite a bit since then.
Fast forward to today. Modernization has come from three different sources – the server hypervisor, the storage hypervisor and the unified recovery manager. The end result is a data protection environment that captures all the data it needs in one coordinated snapshot action, efficiently stores those snapshots, and provides for recovery of just about any slice of data you could want. It’s quite the beautiful thing."
At this point, you might scratch your head and ask "Does this Storage Hypervisor exist, or is this just a theoretical exercise?" The answer of course is "Yes, it does exist!" Just like VMware offers vSphere and vCenter, IBM offers block-level disk virtualization through the SAN Volume Controller(SVC) and Storwize V7000 products, with a full management support from Tivoli Storage Productivity Center Standard Edition.
SVC has supported every release of VMware since the 2.5 version. IBM is the leading reseller of VMware, so it makes sense for IBM and VMware development to collaborate and make sure all the products run smoothly together. SVC presents volumes that can be formatted for VMFS file system to hold your VMDK files, accessible via FCP protocol. IBM and VMware have some key synergies:
Management integration with Tivoli Storage Productivity Center and VMware vCenter plug-in
VAAI support: Hardware-assisted locking, hardware-assisted zeroing, and hardware-assisted copying. Some of the competitors, like EMC VPLEX, don't have this!
Space-efficient FlashCopy. Let's say you need 250 VM images, all running a particular level of Windows. A boot volume of 20GB each would consume 5000GB (5 TB) of capacity. Instead, create a Golden Master volume. Then, take 249 copies with space-efficient FlashCopy, which only consumes space for the modified portions of the new volumes. For each copy, make the necessary changes like unique hostname and IP address, changing only a few blocks of data each. The end result? 250 unique VM boot volumes in less than 25GB of space, a 200:1 reduction!
Support for VMware's Site Recovery Manager using SVC's Metro Mirror or Global Mirror features for remote-distance replication.
Data center federation. SVC allows you to seamlessly do vMotion from one datacenter to another using its "stretched cluster" capability. Basically, SVC makes a single image of the volume available to both locations, and stores two physical copies, one in each location. You can lose either datacenter and still have uninterrupted access to your data. VMware's HA or Fault Tolerance features can kick in, same as usual.
But unlike tools that work only with VMware, IBM's storage hypervisor works with a variety of server virtualization technologies, including Microsoft Hyper-V, Xen, OracleVM, Linux KVM, PowerVM, z/VM and PR/SM. This is important, as a recent poll on the Hot Aisle blog indicates that [44 percent run 2 or more server hypervisors]!
Join the conversation! The virtual dialogue on this topic will continue in a [live group chat] this Friday, September 23, 2011 from 12 noon to 1pm EDT. Join me and about 20 other top storage bloggers, key industry analysts and IBM Storage subject matter experts to discuss storage hypervisors and get questions answered about improving your private storage environment.
Did IBM XIV force EMC's hand to announce VMAXe? Let's take a stroll down memory lane.
In 2008, IBM XIV showed the world that it could ship a Tier-1, high-end, enterprise-class system using commodity parts. Technically, prior to its acquisition by IBM, the XIV team had boxes out in production since 2005. EMC incorrectly argued this announcement meant the death of the IBM DS8000. Just because EMC was unable to figure out how to have more than one high-end disk product, doesn't mean IBM or other storage vendors were equally challenged. Both IBM XIV and DS8000 are Tier-1, high-end, enterprise-class storage systems, as are the IBM N series N7900 and the IBM Scale-Out Network Attached Storage (SONAS).
In April 2009, EMC followed IBM's lead with their own V-Max system, based on Symmetrix Engenuity code, but on commodity x86 processors. Nobody at EMC suggested that the V-Max meant the death of their other Symmetrix box, the DMX-4, which means that EMC proved to themselves that a storage vendor could offer multiple high-end disk systems. Hitachi Data Systems (HDS) would later offer the VSP, which also includes some commodity hardware as well.
In July 2009, analysts at International Technology Group published their TCO findings that IBM XIV was 63 percent less expensive than EMC V-Max, in a whitepaper titled [COST/BENEFIT CASE
FOR IBM XIV STORAGE SYSTEM Comparing Costs for IBM XIV and EMC V-Max Systems]. Not surprisingly, EMC cried foul, feeling that EMC V-Max had not yet been successful in the field, it was too soon to compare newly minted EMC gear with a mature product like XIV that had been in production accounts for several years. Big companies like to wait for "Generation 1" of any new product to mature a bit before they purchase.
To compete against IBM XIV's very low TCO, EMC was forced to either deeply discount their Symmetrix, or counter-offer with lower-cost CLARiiON, their midrange disk offering. An ex-EMCer that now works for IBM on the XIV sales team put it in EMC terms -- "the IBM XIV provides a Symmetrix-like product at CLARiiON-like prices."
(Note: Somewhere in 2010, EMC dropped the hyphen, changing the name from V-Max to VMAX. I didn't see this formally announced anywhere, but it seems that the new spelling is the officially correct usage. A common marketing rule is that you should only rename failed products, so perhaps dropping the hyphen was EMC's way of preventing people from searching older reviews of the V-Max product.)
This month, IBM introduced the IBM XIV Gen3 model 114. The analysts at ITG updated their analysis, as there are now more customers that have either or both products, to provide a more thorough comparison. Their latest whitepaper, titled [Cost/Benefit Case for IBM XIV Systems: Comparing Cost
Structures for IBM XIV and EMC VMAX Systems], shows that IBM maintains its substantial cost savings advantage, representing 69 percent less Total Cost of Ownership (TCO) than EMC, on average, over the course of three years.
In response, EMC announced its new VMAXe, following the naming convention EMC established for VNX and VNXe. Customers cannot upgrade VNXe to VNX, nor VMAXe to VMAX, so at least EMC was consistent in that regard. Like the IBM XIV and XIV Gen3, the new EMC VMAXe eliminated "unnecessary distractions" like CKD volumes and FICON attachment needed for the IBM z/OS operating system on IBM System z mainframes. Fellow blogger Barry Burke from EMC explains everything about the VMAXe in his blog post [a big thing in a small package].
So, you have to wonder, did IBM XIV force EMC's hand into offering this new VMAXe storage unit? Surely, EMC sales reps will continue to lead with the more profitable DMX-4 or VMAX, and then only offer the VMAXe when the prospective customer mentions that the IBM XIV Gen3 is 69 percent less expensive. I haven't seen any list or street prices for the VMAXe yet, but I suspect it is less expensive than VMAX, on a dollar-per-GB basis, so that EMC will not have to discount it as much to compete against IBM.
The new [IBM System Storage Tape Controller 3592 Model C07] is an upgrade to the previous C06 controller. Like the C06, the new 3592-C07 can have up to four FICON (4Gbps) ports, four FC ports, and connect up to 16 drives. The difference is that the C07 supports 8Gbps speed FC ports, and can support the [new TS1140 tape drives that were announced on May 9]. A cool feature of the C07 is that it has a built-in library manager function for the mainframe. On the previous models, you had to have a separate library manager server.
Crossroads ReadVerify Appliance (3222-RV1)
IBM has entered an agreement to resell [Crossroads ReadVerify Appliance], or "RV1" for short. The RV1 is a 1U-high server with software that gathers information on the utilization, performance and health for a physical tape environment, such as an IBM TS3500 Tape Library. The RV1 also offers a feature called "ArchiveVerify" which validates long-term retention archive tapes, providing an audit trail on the readability of tape media. This can be useful for tape libraries attached behind IBM Information Archive compliance storage solution, or the IBM Scale-Out Network Attached Storage (SONAS).
As an added bonus, Crossroads has great videos! Here's one, titled [Tape Sticks]
Linear Tape File System (LTFS) Library Edition Version 2.1
While the hardware is all refreshed, the overall "scale-out" architecture is unchanged. Kudos to the XIV development team for designing a system that is based entirely on commodity hardware, allowing new hardware generations to be introduced with minimal changes to the vast number of field-proven software features like thin provisioning, space-efficient read-only and writeable snapshots, synchronous and asynchronous mirroring, and Quality of Service (QoS) performance classes.
The new XIV Gen3 features an Infiniband interconnect, faster 8Gbps FC ports, more iSCSI ports, faster motherboard and processors, SAS-NL 2TB drives, 24GB cache memory per XIV module, all in a single frame IBM rack that supports the IBM Rear Door Heat Exchanger. The results are a 2x to 4x boost in performance for various workloads. Here are some example performance comparisons:
Disclaimer: Performance is based on measurements and projections using standard IBM benchmarks in a controlled environment. The actual throughput that any user will experience will vary depending upon considerations such as the amount of multiprogramming in the user's job stream, the I/O configuration, the storage configuration, and the workload processed. Therefore, no assurance can be given that an individual user will achieve throughput improvements equivalent to the performance ratios stated here. Your mileage may vary.
In a Statement of Direction, IBM also has designed the Gen3 modules to be "SSD-ready" which means that you can insert up to 500GB of Solid-State drive capacity per XIV module, up to 7.5TB in a fully-configured 15 module frame. This SSD would act as an extension of DRAM cache, similar to how Performance Accelerator Modules (PAM) on IBM N series.
IBM will continue to sell XIV Gen2 systems for the next 12-18 months, as some clients like the smaller 1TB disk drives. The new Gen3 only comes with 2TB drives. There are some clients that love the XIV so much, that they also use it for less stringent Tier 2 workloads. If you don't need the blazing speed of the new Gen3, perhaps the lower cost XIV Gen2 might be a great fit!
As if I haven't said this enough times already, the IBM XIV is a Tier-1, high-end, enterprise-class disk storage system, optimized for use with mission critical workloads on Linux, UNIX and Windows operating systems, and is the ideal cost-effective replacement for EMC Symmetrix VMAX, HDS USP-V and VSP, and HP P9000 series disk systems, . Like the XIV Gen2, the XIV Gen3 can be used with IBM System i using VIOS, and with IBM System z mainframes running Linux, z/VM or z/VSE. If you run z/OS or z/TPF with Count-Key-Data (CKD) volumes and FICON attachment, go with the IBM System Storage DS8000 instead, IBM's other high-end disk system.