From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753325AbXC2J1m (ORCPT ); Thu, 29 Mar 2007 05:27:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753323AbXC2J1m (ORCPT ); Thu, 29 Mar 2007 05:27:42 -0400 Received: from out4.smtp.messagingengine.com ([66.111.4.28]:53491 "EHLO out4.smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753325AbXC2J1l (ORCPT ); Thu, 29 Mar 2007 05:27:41 -0400 X-Greylist: delayed 1883 seconds by postgrey-1.27 at vger.kernel.org; Thu, 29 Mar 2007 05:27:40 EDT X-Sasl-enc: CLDZHoEHmKqhTFi1xCC6YPw3RvrV0c1bPqG+mx4VYeS1 1175158577 Date: Thu, 29 Mar 2007 05:56:12 -0300 From: Henrique de Moraes Holschuh To: Justin Piszcz Cc: Neil Brown , linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org Subject: Re: Software RAID (non-preempt) server blocking question. (2.6.20.4) Message-ID: <20070329085612.GA19278@khazad-dum.debian.net> References: <17931.23488.160031.119117@notabene.brown> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-GPG-Fingerprint: 1024D/1CDB0FE3 5422 5C61 F6B7 06FB 7E04 3738 EE25 DE3F 1CDB 0FE3 User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 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