RAID 0 4k Random Read/Write
We precondition the array of eight HGST SSD800MH for 9,000 seconds, or two and a half hours, receiving performance reports every second. We plot this data to illustrate the drives' descent into steady state.
This dual-axis chart consists of 18,000 data points, with the IOPS on the left and the latency on the right. The red dots signify IOPS, and the grey dots are latency measurements during the test. We place latency data in a logarithmic scale to bring it into comparison range. The lines through the data scatter are the average during the test. This type of testing presents standard deviation and maximum/minimum I/O in a visual manner.
Note that the IOPS and Latency figures are nearly mirror images of each other. This illustrates that high-granularity testing can give our readers a good feel for latency distribution by viewing IOPS at one-second intervals. This should be in mind when viewing our test results below. This downward slope of performance only happens during the first few hours of use, and we present precondition results only to confirm steady state convergence.
Each level tested includes 300 data points (five minutes of one second reports) to illustrate performance variability. The line for each (Outstanding I/O) OIO depth represents the average speed reported during the five-minute interval. 4k random speed measurements are an important metric when comparing drive performance as the hardest type of file access for any storage solution to master is small-file random. One of the most sought-after performance specifications, 4k random performance is a heavily marketed figure.
The 9361-8i averages 557,037 IOPS, trailing the Adaptec ASR-8885, which scores an average of 685,760 IOPS at 256 OIO. Interestingly, the 9361-8 scores well at lower OIO, nearly doubling the performance of the ASR-8885 at 64 OIO.
The ASR-8885 has lower latency at 128 and 256 OIO, but the 9361-8i exhibits much lower latency at lower OIO, staying well under .15ms until 128 OIO.
The 9361-8i regains its footing in the random workload with a maximum speed of 578,287 IOPS, while the ASR-8885 trails slightly with an average of 535,766 IOPS at 256 OIO. Once again, we note the enhanced scaling with lower OIO loads from the 9361-8i.
The 9361-8i maintains lower latency during write testing.
Our write percentage testing illustrates the varying performance of each solution with mixed workloads. The 100 percent column to the right is a pure 4k write workload, and 0 percent represents a pure 4k read workload.
The 9361-8i has a propensity for 4k write workloads. It trails in pure read workloads but takes the lead in heavier write environments.