More MSA performance

Since my OES benchmark went so well, I've been asked to do a series on the MSA we just received for our BCC cluster. Long time readers will remember that the BCC cluster will be done with free or cheap software, not Novell BCC. Unfortunately, the same goes for the hardware. So I get to find out if the MSA will really live up to our performance expectations.

The testing series I've worked out is this:
  1. RAID stripe performance (standard IOZONE, and a 32GB file IOZONE)
    1. 64K both Raid0 and Raid5
    2. Default stripes: 16K Raid5, and 128K Raid0
    3. Versus EVA performance
  2. Software mirror performance (software Raid1)
    1. Windows/NetWare: MSA/EVA
    2. Windows: MSA/MSA
    3. ?? Windows: EVA/EVA
  3. Concurrency performance
    1. Multiple high-rate streams to the same Disk Array (different logical drives)
    2. Multiple high-rate streams to different Disk Arrays
    3. Random I/O & Sequential I/O performance interaction on the same array
The dark green ones are the steps I've completed so far. I'm in the process of restriping for the 16K/128K stripes, which will probably take the rest of the day to complete. I may be able to start off the testing series before I go home tonight. If so, it'll probably get done sometime Sunday evening.

One thing the testing has already shown, and that is for Raid5 performance a quiescent MSA out-performs the in-production EVA. Since there is no way to do tests against the EVA without competing at the disk level for I/O supporting production, I can't get a true apples to apples comparison. By the numbers, EVA should outperform MSA. It's just that classes have started to the EVA is currently supporting the 6 node NetWare cluster and the two node 8,000 mailbox Exchange cluster, where the MSA is doing nothing but being subjected to benchmarking loads.

The other thing that is very apparent in the tests are the prevalence of caching. Both the host server and the MSA have caching. The host server is more file-based caching, and the MSA (512MB) is block-level caching. This has a very big impact on performance numbers for files under 512MB. This is why the 32GB file test is very important to us, since that test blows past ALL caching and yields the 'worst case' performance numbers for MSA.

Tags: ,