As with all of our tests, the following tests were performed after a secure erase of the drives. The drives were also conditioned with a predefined workload until they reached steady state. We also test across the entire span of the drives.
Random 4KiB performance on the ASR-72405 is great. We consistently hit 370,000 IOPS on both read and write operations. When we doubled up on the ASR-72405s, we had no problem clearing 700,000 IOPS. What was interesting was that if your queue depth was below 96, there wasn’t a dramatic difference between one and two ASR-72405s. If fact, for 4KiB random writes, the single ASR-72405 actually bested the 2x setup.
Sequential performance is really where the ASR-72405 shines. We observed over 6600MB/s in 1MB sequential writes and 6400MB/s in sequential reads. In RAID 5, sequential writes were well above Adaptec’s numbers at 3GB/s, while sequential reads matched the RAID 0 performance. The ASR-72405 needs a little bit larger queue depth for read operations in order to hit maximum speed.
So what happens when we used two ASR-72405s? Why, we doubled our performance, of course. We actually hit 12GB/s for sequential writes and nearly 11GB/s for sequential reads. That is an amazing number. That means, between the two ASR-72405s, each SSD was writing at its maximum speed. Now, in order to hit those numbers, we had to throw an extremely large number of outstanding IOs at the ASR-72405s, but that is more normal in enterprise installations.