RAID 5 4k Random Read/Write
We notice much more differentiation between the two controllers in RAID 5 testing, especially in write workloads. We start with a 4k random read workload that the ASR-8885 leads with an outstanding average of 685,760 IOPS at 256 OIO. The 9361-8i averages 557,037 IOPS at the highest workloads, but it again exhibits solid scaling at the lower-end.
The 9361-8i tops out at 48,554 IOPS at 128 OIO and then slows down to 45,639 IOPS at 256 OIO. The ASR-8885 reaches its peak of 31,057 at 32 OIO and then drops rapidly to a low of 22,929 at 256 OIO. While both controllers exhibit performance degradation at the highest loading, the LSI weathers the slight dip easily. The ASR-8885 has more profound degradation with heavy write performance scaling.
The latency measurements reflect a nearly 2X advantage for the 9361-8i at 256 OIO.
Write performance scales as we would expect in this test for the 9361-8i. The ASR-8885 leads with a pure read workload, but it hits a massive cliff when we mix in a light 10 percent write workload. The ASR-8885 cedes the rest of the test to the 9361-8i as we mix in more write activity. Even the slightest of write workloads knocks the ASR-8885 off its perch atop the read chart.
We normally do not present some test results, especially if they seem repetitive. We record latency during our mixed workloads, but for simplicities sake, we do not report on 'expected' results.
However, the odd behavior of the ASR-8885 deserves investigation. The LSI plateaus at a 20 percent write workload and is fairly even for the remainder of the test. The ASR-8885 continues to experience increasing latency as we mix in more writes, topping out at a staggering 15.43ms with a 90 percent write workload. We repeated these tests several times to confirm that the results are repeatable.