MULTI-DRIVE PERFORMANCE, cont.
Finally, we get to aggregate throughput. We can’t saturate the 9207-8i with IOPS, but we can harness the throughput of 8 drives.
So, as it turns out, we can make the most of 8 Crucial M4 256GB SATA III SSDs. Read and write throughput scales beautifully. 2.15GB/s for sequential writes is exactly 8x the seq. write speed of one M4, while 4.18GB/s is exactly 8x the seq. read speed. Had this been a PCIe 2 device, read scaling would have stopped with five drives or so, being that overhead limits theoretical bandwidth by 20%. The M4s only write half as fast as they read, so they come in under the 3GB/s limit of PCIe 2, but scale well nonetheless.
We’re just scratching the surface with these basic tests. But we wanted to know how much data we could push through the card, and we got our answer. With 8 consumer drives we were able to get almost 4200MB/s read throughput. The octet of Crucials managed just shy of 370,000 write IOPS too.
Naturally, when new gear shows up, we can’t resist the urge to try it out. The 9207-8i is going into our Enterprise Test Bench for more testing, but on it’s way we had to stop and give it a whirl with a few SSDs. The Crucial M4 may itself be supplanted by Micron’s next client drive, but aggressive pricing and considerable speed will make it a mainstay for the foreseeable future. By putting the two products together, we found some excellent performance and perhaps a hint of things to come.
The LSI SAS 9207 HBA is still young, so new developments with respect to drivers and firmware could change performance as it matures. Given LSI’s track record, the 9207-8i has a prosperous future. In contrast, given that 12Gbps products are going to be on the market sooner rather than later, the 9207 could just be a short-term stepping stone to the PCIe 3 12Gbps HBAs of the not-too-distant future. Predicting the future is never easy though, so it’s best not to make any firm prognostications. We’ll take advancements anywhere we can find them, and LSI’s Gen3 HBAs are certainly great advancements if you have the hardware to make the most of it.