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SNIA IOPS TESTING
The Storage Networking Industry Association has an entire industry accepted performance test specification for solid state storage devices. Some of the tests are complicated to perform, but they allow us to look at some important performance metrics in a standard, objective way.
SNIA’s Performance Test Specification (PTS) includes IOPS testing, but it is much more comprehensive than just running 4KiB writes with IOMeter. SNIA testing is more like a marathon than a sprint. In total, there are 25 rounds of tests, each lasting 56 minutes. Each round consists of 8 different block sizes (512 bytes through 1MB) and 7 different access patterns (100% reads to 100% writes). After 25 rounds are finished (just a bit longer than 23 hours), we record the average performance of 4 rounds after we enter steady state.
- Preconditioning: 3x capacity fill with 128K sequential writes
- Each round is composed of .5K, 4K, 8K, 16K, 32K, 64K, 128K, and 1MB accesses
- Each access size is run at 100%, 95%, 65%, 50%, 35%, 5%, and 0% Read/Write Mixes, each for one minute.
- The test is composed of 25 rounds (one round takes 56 minutes, 25 rounds = 1,400 minutes)
This test is normally used for single SSD testing, but it does a good job of showing numerous transfer sizes, mixed operations and quick workload transitions in a single graph. The results for the Adaptec/SMART solution are so outstanding it’s hard to know where to begin. The first thing that stands out is that the 100% read operations stayed right around 360,000 IOPS from 0.5 to 16KiB. The 100% write operations didn’t do quite as well, but the 4 and 8 KiB results were nearly identical.
The 4KiB performance was another result that stood out. Even with a 50/50 mix, the Adaptec/SMART solution still recorded almost 350,000 IOPS, down only slightly from its 368,000 IOPS max.
In many published reports a single optimus cannot provide latency performance within that tight of a range. These are obviously system cache results.
All caching was disabled, except for any write coalescing that the ROC was doing behind the scenes. You have to remember that the SSDs were not the bottleneck on the latency measurements, in fact, they were only going at 40% of their specified rates. Also, every test we have performed, and other sites as well, show the Optimus to be a very stable SSD. So, to your point, there is some amount of caching happening outside of the DRAM, but it very limited.
Any chance of reviewing the 71605Q, see how it stands up with 1 or 2TB worth of SSD cache and a much larger spinning array? Since it comes with the ZMCP (Adaptec’s version of BBU) you can even try it with write caching on.
I’d especially love to see maxCache 3.0 go head to head with LSI CacheCade Pro 2.0
Considering I actually already own the 71605Q, and bought practically “sight unseen” as there are still no reviews available it is nice to see that the numbers on the other cards in the line are living up to their claims.
Like I said in the review, I wish we had the time and resources to test out all combination, but we can’t get them all. I have both the 8 and 24-port versions and, yes, they always hit or exceed their published specifications. I agree, that would be a great head-to-head matchup, We have a lot of great RAID stories coming up, maybe we can fit it in. Thanks for the feedback!
Yeah after I posted that I started brainstorming all the possible valid combinations you could test with those two cards and there’s quite a few permutations… Also might not be too fair to the older LSI solution but it’s what they have available and I don’t know of any release schedule for CC 3.0 or next gen cards, so might not hurt to wait for those.
I guess the best case to test would be best case cache worst case spinners, so RAID-10/1E SSDs with RAID-6 HDDs. See how the two solutions do at overcoming some of the RAID-6 drawbacks esp the write penalty.
I’m guessing the results would probably be fairly similar to the LSI Nytro review but still would be interesting to see how up to 2TB of SMART Optimus would do with a 20TB array.
Nice! How did you manage to connect the two cards (X2)?
“..We were able to procure a second ASR-72405 and split the drives evenly across the two…”
See my comment
I’m assuming they made a stripe on each raid card and then did a software raid 0 stripe of the arrays into one volume. That would be why the processors showed 50% until under load.
Great review though that SSD has me worried for sustained enterprise usage.