On Fri, Feb 03, 2012 at 01:42:54PM -0600, Stan Hoeppner wrote: > You've hit the peak read rate of these Hitachi drives. As others > pointed out, if you need more read performance than the dozen of these > you plan to RAID stripe, then you'll need to swap them for units with a > faster spindle: > > 7.2k 1.21x > 10k 1.68x > 15k 2.53x > > or with SSDs, which will yield an order of magnitude increase. Your > stated need is 20M 500-800KB files, or 20GB if my math is correct. Thanks for your suggestion, but unfortunately your maths isn't correct: 20M x 0.65MB = 13TB. And that's just one of many possible datasets like this. I'm aware that I'm working with low-performance drives. This is intentional: we need low power consumption so we can get lots in a rack, and large capacity at low cost. Fortunately our workload will also parallelise easily, and throwing it across 24 spindles will be fine. But obviously I want to squeeze the most performance out of each spindle we have first. I'm very happy to have found the bottleneck that was troubling me :-) Regards, Brian. _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
