Last week, in Computer Technology Review's article [Tiering: Scale Up? Scale Out? Do Both], Mark Ferelli interviews fellow blogger Hu Yoshida, CTO of Hitachi Data Systems (HDS). Here's an excerpt:
This is not the first time I have had to correct Hu and others of misperceptions of IBM's SAN Volume Controller (SVC). This month marks my four year "blogoversary", and I seem to spend a large portion of my blogging time setting the record straight. Here are just a few of my favorite posts setting the record straight on SVC back in 2007:
Since day 1, SAN Volume Controllers has focused primarily on external storage. Initially, the early models had just battery-protected DRAM cache memory, but the most recent model of the SVC, the 2145-CF8, adds support for internal SLC NAND flash solid state drives. To fully appreciate how SVC can help improve the performance of the disks that are managed, I need to use some visual aids.
In this example, the SVC reduced the burden of the managed disk from 100,000 IOPS down to 55,000, which is 35,000 reads and 20,000 writes. Some have argued against putting one level of cache (SVC) in front of another level of cache (managed disk arrays). However, CPU processor designers have long recognized the value of hierarchical cache with L1, L2, L3 and sometimes even L4 caches. The cache-hits on SVC are faster than most disk system's cache-hits.
Of course, not all workloads are 70/30/50, and not every disk array is driven to its maximum capability, so your mileage may vary. As we slide down the left of the curve where things are flatter, the improvement in performance lowers.
Hitachi's offerings, including the HDS USP-V, USP-VM and their recently announced Virtual Storage Platform (VSP) sold also by HP under the name P9500, have similar architecture to the SVC and can offer similar benefits, but oddly the Hitachi engineers have decided to treat externally attached storage as second-class citizens instead. Hu mentions data that "ages out or becomes less active we can move it to the external storage." IBM has chosen not to impose this "caste" system onto its design of the SAN Volume Controller.
The SVC has been around since 2003, before the USP-V came to market, and has sold over 20,000 SVC nodes over the past seven years. The SVC can indeed improve performance of managed disk systems, in some cases by a substantial amount. The 0.06 msec latency on read-miss requests represents less than 1 percent of total performance in production workloads. SVC nearly always improves performance, and in the worst case, provides same performance but with added functionality and flexibility. For the most part, the performance boost comes as a delightful surprise to most people who start using the SVC.
This week, Hitachi Ltd. announced their next generation disk storage virtualization array, the Virtual Storage Platform, following on the success of its USP V line. It didn't take long for fellow blogger Chuck Hollis (EMC) to comment on this in his blog post [Hitachi's New VSP: Separating The Wheat From The Chaff]. Here are some excerpts:
Chuck implies that neither Hewlett-Packard (HP) nor Hitachi Data Systems (HDS) as vendors provide any value-add from the box manufactured by Hitachi Ltd. so combines them into a single category. I suspect the HP and HDS folks might disagree with that opinion.
When I reminded Chuck that IBM was also a major player in the high-end disk space, his response included the following gem:
"Many of us in the storage industry believe that IBM currently does not field a competitive high-end storage platform. IDC market share numbers bear out this assertion, as you probably know."
While Chuck is certainly entitled to his own beliefs and opinions, believing the world is flat does not make it so. Certainly, I doubt IDC or any other market research firm has put out a survey asking "Do you think IBM offers a competitive high-end disk storage platform?" Of course, if Chuck is basing his opinion on anecdotal conversations with existing EMC customers, I can certainly see how he might have formed this misperception. However, IDC market share numbers don't support Chuck's assertion at all.
There is no industry-standard definition of what is a "high-end" or "enterprise-class" disk system. Some define high-end as having the option for mainframe attachment via ESCON and/or FICON protocol. Others might focus on features, functionality, scalability and high 99.999+ percent availability. Others insist high-end requires block-oriented protocols like FC and iSCSI, rather than file-based protocols like NAS and CIFS.
For the most demanding mission-critical mix of random and sequential workloads, IBM offers the [IBM System Storage DS8000 series] high-end disk system which connects to mainframes and distributed servers, via FCP and FICON attachment, and supports a variety of drive types and RAID levels. The features that HP and HDS are touting today for the VSP are already available on the IBM DS8000, including sub-LUN automatic tiering between Solid-State drives and spinning disk, called [Easy Tier], thin provisioning, wide striping, point-in-time copies, and long distance synchronous and asynchronous replication.
There are lots of analysts that track market share for the IT storage industry, but since Chuck mentions [IDC] specifically, I reviewed the most recent IDC data, published a few weeks ago in their "IDC Worldwide Quarter Disk Storage Tracker" for 2Q 2010, representing April 1 to June 30, 2010 sales. Just in case any of the rankings have changed over time, I also looked at the previous four quarters: 2Q 2009, 3Q 2009, 4Q 2009 and 1Q 2010.
(Note: IDC considers its analysis proprietary, out of respect for their business model I will not publish any of the actual facts and figures they have collected. If you would like to get any of the IDC data to form your own opinion, contact them directly.)
In the case of IDC, they divide the disk systems into three storage classes: entry-level, midrange and high-end. Their definition of "high-end" is external RAID-protected disk storage that sells for $250,000 USD or more, representing roughly 25 to 30 percent of the external disk storage market overall. Here are IDC's rankings of the four major players for high-end disk systems:
By either measure of market share, units (disk systems) or revenue (US dollars), IDC reports that IBM high-end disk outsold both HDS and HP combined. This has been true for the past five quarters. If a smaller start-up vendor has single digit percent market share, I could accept it being counted as part of Chuck's "occasional sideshow from other vendors trying to claim relevance", but IBM high-end disk has consistently had 20 to 30 percent market share over the past five quarters!
Not all of these high-end disk systems are connected to mainframes. According to IDC data, only about 15 to 25 percent of these boxes are counted under their "Mainframe" topology.
Chuck further writes:
"It's reasonable to expect IBM to sell a respectable amount of storage with their mainframes using a protocol of their own design -- although IBM's two competitors in this rather proprietary space (notably EMC and Hitachi) sell more together than does IBM."
The IDC data doesn't support that claim either, Chuck. By either measure of market share, units (disk systems) or revenue (US dollars), IDC reports that IBM disk for mainframes outsold all other vendors (including EMC, HDS, and HP) combined. And again, this has been true for the past five quarters. Here is the IDC ranking for mainframe disk storage:
IBM has over 50 percent market share in this case, primarily because IBM System Storage DS8000 is the industry leader in mainframe-related features and functions, and offers synergy with the rest of the z/Architecture stack.
So Chuck, I am not picking a fight with you or asking you to retract or correct your blog post. Your main theme, that the new VSP presents serious competition to EMC's VMAX high-end disk arrays, is certainly something I can agree with. Congratulations to HDS and HP for putting forth what looks like a viable alternative to EMC's VMAX.
Well it's Tuesday again, and you know what that means... IBM Announcements! While most of the attention is going to [IBM's new servers, the zEnterprise 114 and the POWER 775], there were a few [announcements related specifically to storage] that I wanted to discuss.
To learn more, read Jim Kelly's [XIV Gen 3: Both Hands Clapping], and Anthony Vandewerdt's [Brief History of XIV], and Elisabeth Stahl's [Big Day, Big Data, Big Announcements] blog posts, or see the resources on the [XIV resources page].
technorati tags: xiv, rv1, Information Archive, Tape Sticks, 3592, emc, symmetrix, hds, c07, usp-v, crossroads, readverify, hewlett-packard, ltfs, sonas, p9500, vmax, ts3310, ts2900, vsp, archiveverify, ibm, ts3500
Comment (1) Visits (15269)
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:
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!
Comment (1) Visits (10192)
On my last blog post [Is this what HDS tells our mainframe clients?], I poked fun at Hu Yoshida's blog post that contained a graphic with questionable results. Suddenly, the blog post disappeared altogether. Poof! Gone!
Just so that I am not accused of taking a graph out of context, here is Hu's original post, in its entirety:
At this point, you might be wondering: "If Hu Yoshida deleted his blog post, how did Tony get a copy of it? Did Tony save a copy of the HTML source before Hu deleted it?" No. I should have, in retrospect, in case lawyers got involved. It turns out that deleting a blog post does not clear the various copies in various RSS Feed Reader caches. I was able to dig out the previous version from the vast Google repository. (Many thanks to my friends at Google!!!).
The graph itself was hosted separately has been deleted, but it was just taken from slide 10 of the HDS presentation [How to Apply the Latest Advances in Hitachi Mainframe Storage], so it was easy to recreate.
(Lesson to all bloggers: If you write a blog post, and later decide to remove it for whatever legal, ethical, moral reasons, it is better to edit the post to remove offending content, and add a comment that the post was edited, and why. Shrinking a 700-word article down to 'Sorry Folks - I decided to remove this blog post because...' would do the trick. This new edited version will then slowly propagate across to all of the RSS Feed Reader caches, eliminating most traces to the original. Of course, the original may have been saved by any number of your readers, but at least if you have an edited version, it can serve as the official or canonical version.)
Perhaps there was a reason why HDS did not want to make public the FUD its sales team use in private meetings with IBM mainframe clients. Whatever it was, this appears to be another case where the cover-up is worse than the original crime!