Update (5/2): This was resolved. Adaptec worked with me directly on this issue. The issue was confirmed, identified and a fix was found. The fixed firmware will be released in the next official release which is promised to be delivered later this month. For now I recommend you don’t use builds 30612<x<=30862 of the firmware. Glad to be able to help squash a bug and looking forward to testing the new version.
A few weeks ago we got a batch of new servers at ClickTale and started doing acceptance testing on them. Surprisingly enough, those sweet dual deca-core servers failed to pass the IO acceptance tests. I have posted on the subject of IO benchmarking in the past and for those of you who don’t know already I take performance measuring very seriously.
The problematic measurements were sequential reads as measured by CrystalDiskMark. It seems, on new servers, when controller (read) cache was enabled on the logical device, sequential read speeds were lower than usual and, for many Simple Volume and Raid1 devices, capped at around 100MB. Also, Raid1 devices that are supposed to provide improved read performance vs just a single simple disk were not providing such improvements.