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
--
Troy Engel | Systems Engineer
Fluid, Inc | http://www.fluid.com
