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 4KB 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)
As we mentioned before, we performed most of our tests at a queue depth of 384. SNIA does not actually specify a specific queue depth, so we default to 32 unless otherwise noted.
The Adaptec/HGST solution had absolutely no problems with the SNIA testing. You can see that we hit the card maximums at both 512 bytes and 4KB. We even hit an impressive 650K IOPS for 8KB reads. Across the testing, we saw wonderful scaling, even in some of the most strenuous workloads. Once we hit steady-state, the performance was 100% reliable, whether we ran our tests for a minute, an hour, or a day.