From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brad Campbell Subject: Re: RAID-6 check slow.. Date: Tue, 22 Aug 2006 12:07:16 +0400 Message-ID: <44EABB34.60603@wasp.net.au> References: <44EAB1B7.7010208@wasp.net.au> <17642.47012.109307.542850@cse.unsw.edu.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <17642.47012.109307.542850@cse.unsw.edu.au> Sender: linux-raid-owner@vger.kernel.org To: Neil Brown Cc: RAID Linux List-Id: linux-raid.ids Neil Brown wrote: > Hmm.... nothing obvious. > Have you tried increasing > /proc/sys/dev/raid/speed_limit_min:1000 > just in case that makes a difference (it shouldn't but you seem to be > down close to that speed). No difference.. > What speed in the raid6 algorithm used - as reported at boot time? > Again, I doubt that is the problem - if should be about 1000 times > speed you are seeing. raid6: int32x1 739 MB/s raid6: int32x2 991 MB/s raid6: int32x4 636 MB/s raid6: int32x8 587 MB/s raid6: mmxx1 1556 MB/s raid6: mmxx2 2701 MB/s raid6: sse1x1 1432 MB/s raid6: sse1x2 2398 MB/s raid6: using algorithm sse1x2 (2398 MB/s) md: raid6 personality registered for level 6 raid5: automatically using best checksumming function: pIII_sse pIII_sse : 2345.000 MB/sec raid5: using function: pIII_sse (2345.000 MB/sec) md: md driver 0.90.3 MAX_MD_DEVS=256, MD_SB_DISKS=27 md: bitmap version 4.39 > What if you try increasing /sys/block/md0/md/stripe_cache_size ? I already have this at 8192 (which appears to be HUGE for 15 drives, but I've got 1.5GB of ram and nothing else using it) > That's all I can think of for now. > Oh well, no stress.. Just thought I'd ask anyway :) Brad -- "Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so." -- Douglas Adams