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 04:11:37 -0400 (EDT) Message-ID: References: <17931.23488.160031.119117@notabene.brown> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Return-path: In-Reply-To: <17931.23488.160031.119117@notabene.brown> Sender: linux-kernel-owner@vger.kernel.org To: Neil Brown Cc: linux-kernel@vger.kernel.org, linux-raid@vger.kernel.org List-Id: linux-raid.ids On Thu, 29 Mar 2007, Neil Brown wrote: > On Tuesday March 27, jpiszcz@lucidpixels.com wrote: >> I ran a check on my SW RAID devices this morning. However, when I did so, >> I had a few lftp sessions open pulling files. After I executed the check, >> the lftp processes entered 'D' state and I could do 'nothing' in the >> process until the check finished. Is this normal? Should a check block >> all I/O to the device and put the processes writing to a particular device >> in 'D' state until it is finished? > > No, that shouldn't happen. The 'check' should notice any other disk > activity and slow down if anything else is happening on the device. > > Did the check run to completion? And if so, did the 'lftp' start > working normally again? Yes it did and the lftp did start working normally again. > > 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 > > NeilBrown >