Test System and Methodology
We will be testing the 9211-8i head to head with the 9207-8i to quantify the increase in performance with the next generation LSI HBAs. There is the possibility of using the IR firmware, Windows RAID or third party program to aggregate the performance of all of the drives into one large RAID 0 volume. There is also the option for RAID 1, 1E and 10 with the IR firmware.
The configuration that we have tested with provides the best latency results and does a good job of showing the base performance of the 9207-8i Mustang. This is simply configuring the SSDs as separate volumes and accessing each individually. This provides low overall latency in conjunction with much lower maximum latencies than RAID 0. This portion of testing also adheres to our SNIA Specification based testing regimen. More information on our enterprise testing regimen can be found here.
The fun of testing HBA and RAID controllers is that we can use the fastest SSDs that are at our disposal in Fresh out of Box (F.O.B.) conditions. One of the more tedious aspects of standard enterprise testing is the long drawn out conditioning runs to push the SSDs into steady state. This can take up to 12 hours for some SSDs and consists of a lot of waiting on our part. With HBA and RAID controller testing we get to secure erase the drives repetitively to keep them at the absolute top speed. We are trying to measure the speed of the controller and not the attached storage. For a guy who spends 50+ hours a week waiting on steady state conditioning runs to complete, this is liberating!
One of the challenges that we ran into when testing the 9207-8i Mustang was simply being able to saturate the performance of the adapter, so we tested with SSDs to get as close as possible. There currently aren't many SSDs on the market that will be able to saturate the 9207-8i with only eight devices in both throughput and IOPS, so we are forced to take a two-pronged approach.
For throughput testing we turn to our trusty Crucial RealSSD C400 drives. Physically identical to the consumer M4, this 8 x 256GB array of SSDs has served us well in our testing by offering solid and consistent performance. Providing per drive read speeds of 500MB/s and 260MB/s write speeds, we can saturate the read bandwidth of the 9207-8i, but not the write bandwidth.
The second prong of our attack consists of the SanDisk ESS Lightning LS 300S EFDs (Enterprise Flash Devices). The LS 300S are 300GB SLC enterprise class SSDs that come in both a 3.5" and 2.5" form factor. These drives are made for taking a beating and are warrantied for five years of unlimited writing with no throttling. They are simply solid as a rock, offering consistent performance regardless of the workload.
Rated at a blistering 160,000 IOPS per device, they are definitely the heavyweights of enterprise flash storage, even though we are using the 3Gb/s versions. There simply are not many devices that can lay claim to this type of performance, but even with the staggering performance possible, we still cannot saturate the 9207-8i. The 9207-8i Mustang can handle up to 700,000 IOPS, so even with perfect scaling we will be just shy of being able to saturate the adapter. This speaks volumes to the capabilities of the 9207-8i.