David Thompson wrote:
Peter =?iso-8859-1?q?Kjellstr=F6m?= wrote:
raid5, #2 I can't get good read performance on two raid5s in a lvm stripe).
Yeah, we've also seen performance issues with raid5 on the 9500 series products. The benchmarks we run look good, but when we've put them into
As per an old thread on the list, I have a new 9500S-12 and am seeing the same performance problems. But, I'm fairly sure it's because without the BBU installed write-cache is disabled. I have ordered the BBU and expect here soon, I'll see if I can't post some pre-BBU/write cache and post-BBU/write cache numbers, if I find a good test.
Right now I'm running Arkeia on it as the backup-to-disk, and in the middle of the heaviest use I'm seeing about 50-60% I/O wait, horrible. I'm hoping the write cache is going to help this a lot. (*)
-te
(*) some sar output:
12:00:14 AM CPU %user %nice %system %iowait %idle 12:10:51 AM all 6.44 0.03 4.19 51.05 38.30 12:10:51 AM 0 3.83 0.02 4.28 49.69 42.18 12:10:51 AM 1 9.06 0.03 4.09 52.40 34.41 12:20:08 AM all 7.45 0.02 4.40 52.52 35.61 12:20:08 AM 0 4.08 0.02 4.58 51.36 39.96