RAID 0 8K Random Read/Write
In this preconditioning chart, we note the telltale garbage collection cadence of the DC S3700. The garbage collection routines run on a strict schedule on each SSD, and amazingly, this schedule is precise enough that all of the drives are entering the lower performance state at the same time. With the array only able to go as fast as the slowest member, any one member falling out of sync would lower the performance of the entire array.
We noticed this in several of our workloads, and with the extended time frame of our tests, which spans several days with no reboots, one wonders how long it would take before the drives fall out of sync and the array falls into one steady line of lower performance. We will run extended tests in the future on this same array to satisfy our curiosity, and note the results in the comments below.
8K random read and write speed is a metric that is not tested for consumer use, but for enterprise environments this is an important aspect of performance. With several different workloads relying heavily upon 8K performance, we include this as a standard with each evaluation. Many of our Server Emulations below will also test 8K performance with various mixed read/write workloads.
The average 8K random read speed of the 8 drive array comes in at 30,4667 IOPS at QD256, and the four drive array peaks at QD256 with 155,713 IOPS.
The 8k read latency results indicates that the best performance in latency-sensitive applications for the 8-drive array falls at QD128, and the 4-drive array again performs best at QD64.
The average 8K random write speed of the 8-drive array is 133,529 IOPS at QD256, and 68,026 IOPS for the 4-drive array.
With 8K random writes, the larger array performs best at QD64, while the smaller array excels at very low QD workloads in a pure write environment.