Excuse me Sir, this Violin seems out of Tune

By Mike Ault

In a recent article on the Channel Register website, Violin through Chris Mellor talks about their 3200 Flash Memory Array. Unfortunately in the release there are some claims that require examination if not repudiation. Let’s look at the claims put forth from Violin:

1. Integrated Flash RAID and a sustainable 10-fold performance advantage over leading competitors
2. Scales from 500GB to 10TB
3. Data latency less than 100 microseconds
4. Working life of 10+ years with continuous writes
5. First memory array to scale to more than 140TB in a rack with performance over 2 million IOPS
6. Total cost lowered by more than 50 percent
7. Has RAID protection unlike Oracle’s Exadata
8. Violin is the first company to aggregate Flash as an enterprise storage solution, beyond just a cache strategy

Let’s examine each of these claims.

1. Integrated Flash RAID and a “sustainable 10-fold performance advantage over leading competitors”
   Wrong: While Violin may be an integrated Flash RAID, their only competitor in this market is Texas Memory Systems. Based on the proven 80 microsecond write times (per SPC Benchmark 1™) of the RamSan-620 products, obviously the 10 fold performance claim is patently false. Now in when compared to disks, this is true with virtually all Flash providers.
2. Scales from 500GB to 10TB.
   Wrong: This doesn’t take into account the capacity that must be used for Flash management, wear leveling, RAID etc. Their actual usable capacity at the top end of the range is only 7.5 or so terabytes, compared to the actual usable capacity for the RamSan-630 of 10TB.
3. Data latency less than 100 microseconds.
   Inaccurate: So, what is the reference point of this claim? Is this read, write, or a blended rate? If it is read, then what is write latency? The RamSan-500 provides 15 microsecond read latency (from cache), the RamSan-620/630 products provide 80 microsecond write latency and 250 microsecond read latency (nominal) with generally better latency than reported. In looking at the graphs of latency versus IOPS on the Violin site for the 3200, its latency rapidly increases above the reported 100 microseconds as IOPS increase.
4. Working life of 10+ years with continuous writes.
   Inaccurate: Show me the numbers. Is this 365X24X7 at 220,000 IOPS with 100% writes? 80/20 read/write? As they used to say in math class…show your work. Just going by the numbers (I can send you a spreadsheet) the RamSan-630 with a full Flash load-out will last 27 years at 400K write IOPS, it will be on eBay before it wears out.
5. First memory array to scale to more than 140TB in a rack with performance of over 2 million IOPS.
   Wrong: The RamSan-630 at 10TB usable capacity and 500,000 IOPS in a 3U form factor provides 140TB usable space and 7,000,000 IOPS in a single rack. It was announced in April 2010 (actually earlier than that, but that was the “official” date). The 3200 was announced in May 2010.
6. Total cost lowered more than 50 percent.
   Inaccurate: More hand waving, break it down. For example, what are support costs, the cost of the needed head to provide RAID, and other costs? Total cost compared to what? For example the base cost of a 10TB RamSan-630 is $370K for a full capacity 10TB system ($36/GB usable), which is actually 13.5TB total giving $26/GB. At 200K for a Violin 7.5 TB system (usable) so while it is $20/GB for actual storage, for usable it is $26/GB. Essentially the price is a wash with no real benefit, it is just smoke and mirrors and nowhere near the claimed 50%.  At most a 38% difference, however, what else are they not giving all the facts about?
7. Has RAID protection unlike Oracle’s Exadata
   Wrong: Exadata uses ASM technology which provides striping and mirroring (RAID10) in fact from the numbers reported for the Exadata of actual versus available capacity for an Exadata cell, Exadata appears to be using HIGH redundancy which means 3-way mirroring. So, wrong again, Exadata has RAID capacity and is RAIDed.
8. Violin is the first company to aggregate Flash as an enterprise solution, beyond just a cache strategy.
   Wrong: TMS, with the RamSan-500 (2TB), RamSan-620 (5TB) and RamSan-630 (10TB) products provided the first aggregate Flash enterprise solution. The RamSan-500 was announced in September 2007, the RamSan-620 was announced in April 2009 and the RamSan-630 was announced in April 2010, the Violin 3200 in May 2010. Obviously it is fourth in line, not first.

With so many inaccuracies, can the actual specifications provided really be trusted?

Who's In Charge Here Anyways?

As DBAs we have all seen it, heck, probably done it. We call over to the server administrators for more space for our database files and sometime later we get it. We have no idea how it is configured, where it is located or if it will contend with existing file placements. All of the files we own are located in some magic land, let’s call it SAN Land, where everything is always load balanced, there are no hot spots and nothing ever contends with anything else. I think it is located right next to Lake Woebegone.

The SAN as a blackbox technology has been a boon and a bane to Oracle administrators. We know how things should be set up but when we try to pass along this information to the SAN administrator we hear the usual replies about how we have to co-exist with the other users and it is just not possible to configure things just for us. Well, those days have ended.

How about space that doesn’t have to be configured with an eye towards contention due to head movement or contention caused by block placement? How about freedom from hotspots and all the other problems which plague disk based technology? Even better, how about storage that can be locally managed? Impossible? Am I in a fantasy land somewhere?

Nope, not a fantasy land, welcome to the year 2010. How about 225 to 450 gigabytes of low latency storage that is locally controlled and doesn’t depend on disks, and better yet, can usually be purchased and installed with little pushback from system or LAN administrators? The RamSan-10 or RamSan-20 provide 225-450 gigabytes of high speed – low latency SLC flash memory based storage that plugs into a full size PCIe slot in the server and looks like another disk drive, but looks are deceiving.

As a “database accelerator” for a single server database that hooks directly into the server and doesn’t require any fibre channel, NFS, iSCSI or SAS connection, PCIe storage bypasses many of the management headaches associated with standard SAN technology. Due to the RamSans not being dependent on a physical device, 100% of the storage capacity can be utilized, no need to worry about short-stroking, striping or mirroring to get better performance. At a price of between 8-20K USD these solutions also fall easily within the signatory purchase powers of most department heads.

So shake off the fetters of the SAN world and step into the 21^st century! Deliver 5 times the performance of standard SAN technologies to your database that you control locally.

Day 2 of Collaborate 2010

Well, survived day 2! The 1:30-2pm Theater session was packed full, the only issue was that there was no microphone so after having to project above the background noise from the exhibit hall I was a little horse but that's ok. The second presentation for me was actually a RAC Tuning panel from 4-5pm and it went well with lots of great questions and answers.

I attended two of the RAC tuning bootcamp presentations and it was interesting to see that RAC tuning really hasn't changed much from version 9 to version 11 as some of the same things I used to teach when I was consulting are still being used.

Today I have a 1-2pm RAC Expert Panel in Palm F and my Oracle Holistic Tuning presentation from 4-5pm in Palm F, which will also be a webcast.

Of course I will also be at the booth, number 1645. We are giving away a free PDF version of the Oracle Tuning using SSDs book if you stop by with a thumbdrive, come on by!

Hope to see you there!

Day 1 of Collaborate

Well, here is it the beginning of day two of Collaborate'10. Day one I attended a couple of SSD and ASM presentations and helped setup and man the TMS booth. The presentations I attended didn't thrill me so much but they were interesting in the way that they showed the level of understanding in the Oracle community about SSD and ASM usages.

One problem was that the first presentation about SSDs and Oracle on DELL servers and storage didn't give any hard numbers, but instead the presenter (or perhaps DELL) decided to present normalize numbers. This means that the values are normalized to the worst value (in this case the hard SAS drive latency and IOPS) and the other values are reported as they relate to that number ( a percentage). As a possible buyer of the technology I would want hard numbers to compare to rather than normalized numbers, but then maybe I am odd that way.

The second presentation dealt with ASM and load balancing. Unfortunately it didn't do too deep a dive and didn't cover much anything that wasn't in the manual. Maybe I am jaded.

The booth setup went well and we had many people come by to talk performance and real numbers on the RamSan SSDs. We have the RamSan630 here for demos, it is the latest of the TMS RamSan line offering up to 10 terabytes of capacity with 80 microsecond writes and 250 microsecond reads (no I didn't get that reversed!) and with a full set of fibrechannel cards, 500,000 IOPS.

Today I will be presenting in the mini-theater on "Oracle and SSDs" at 1pm. I will also be participating in the Oracle RAC Tuning Panel at 4pm, see you there! Other than that I will be either attending interesting presentations or at the booth.

Come by and see us! We are booth 1645.

Mike Ault

TMS San Jose Road Show

Well after a rough start (getting there!) the San Jose TMS Road Show was a resounding success. Woody, Levi, Webex (one of our customers) and I addressed a packed room about TMS products and their use in resolving IO bottlenecks in computer architectures.



The audience responded well with many intellient and well thought out questions. With the wide level of expertise we brought to the show we were able to answer all questions asked. These road shows are a definite way to get your questions about using SSD technology answered!



Next week it is off to Chicago for the second road show. If you are in the Chicago area please register (use the link on the blog title) and hopefully we will see you there!



Mike



(I tell about my adventure getting to the road show in my personal blog at http://mikerault.blogspot.com)

Day One of SEOUC

Craig Shallahamer gave the keynote on "A Day in the Life of an Oralce User Process", it was fun and informative. At lunch Charles Garry of Oracle gave a keynote on "Lowering your IT Costs" a discussion of using Oracle 11g Grid technology to lower the cost of computing. He also gave me a great shout out for my presentation.

The first day went great. I gave both of my presentations and got great reviews (as far as I could tell!) I had 25 attendees in my first presentation and about a dozen in my second and for this size conference those are pretty good numbers, especially considering the change of day and time for the second presentation. Since this is a regional/local conference many people leave before the last presentation of the day to beat rush hour and unfortunately that was the slot my second presentation was moved to. But that is OK. The attendees for both the first and second talk asked a lot of good questions and seemed very interested in the technologies discussed.

Today will be just a booth day with Ric and I there until 1:45 to answer questions and talk with folks. After that it is bundle back up into the car and head back to Alpharetta. Next stop: Road Show San Jose, so see you there!

Mike Ault

Off to SEOUC 2010

As soon as the laundry finishes it is pack the car and head off to Charlotte, NC for SEOUC 2010. Since I live in Atlanta, Georgia it is easier to just drive there than to deal with the hassles and expenses of flying.

I'll be giving two presentations at SEOUC:

Testing to Destruction: Part Two (discussing TPC-C and TPC-H testing)
Session: 2, Wednesday, 11:15 am - 12:15 pm

Utilizing ASM Preferred Read Groups to Maximize Oracle Performance
Session: 8, Thursday, 1:45 pm - 2:45 pm

The second one has been moved to Wednesday afternoon but I am not sure of the time so check out the website for the most up to date information!

Mike Ault