From mboxrd@z Thu Jan 1 00:00:00 1970 From: Justin Piszcz Subject: Re: Software RAID (non-preempt) server blocking question. (2.6.20.4) Date: Thu, 29 Mar 2007 05:00:51 -0400 (EDT) Message-ID: References: <17931.23488.160031.119117@notabene.brown> <20070329085612.GA19278@khazad-dum.debian.net> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Return-path: In-Reply-To: <20070329085612.GA19278@khazad-dum.debian.net> Sender: linux-raid-owner@vger.kernel.org To: Henrique de Moraes Holschuh Cc: Neil Brown , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org List-Id: linux-raid.ids On Thu, 29 Mar 2007, Henrique de Moraes Holschuh wrote: > On Thu, 29 Mar 2007, Justin Piszcz wrote: >>> Did you look at "cat /proc/mdstat" ?? What sort of speed was the check >>> running at? >> Around 44MB/s. >> >> I do use the following optimization, perhaps a bad idea if I want other >> processes to 'stay alive'? >> >> echo "Setting minimum resync speed to 200MB/s..." >> echo "This improves the resync speed from 2.1MB/s to 44MB/s" >> echo 200000 > /sys/block/md0/md/sync_speed_min >> echo 200000 > /sys/block/md1/md/sync_speed_min >> echo 200000 > /sys/block/md2/md/sync_speed_min >> echo 200000 > /sys/block/md3/md/sync_speed_min >> echo 200000 > /sys/block/md4/md/sync_speed_min > > md RAID1 resync reacts *extremely* badly to CFQ. Just a data point, you may > want to check on it. Might mean other RAID types also get screwed, and also > that md "check" is also disturbed by CFQ (or disturbs CFQ, whatever). > > I reverted everything here to non-CFQ while the RAID did its resync (which > fixed all issues immediately), and we went back to 2.6.16.x later for other > reasons. > > -- > "One disk to rule them all, One disk to find them. One disk to bring > them all and in the darkness grind them. In the Land of Redmond > where the shadows lie." -- The Silicon Valley Tarot > Henrique Holschuh > I am using the AS scheduler; not CFQ. $ find /sys 2>/dev/null|grep -i scheduler|xargs -n1 cat noop [anticipatory] noop [anticipatory] noop [anticipatory] noop [anticipatory] noop [anticipatory] noop [anticipatory] noop [anticipatory] noop [anticipatory] noop [anticipatory] noop [anticipatory] noop [anticipatory] noop [anticipatory] Justin.