From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: RAID extremely slow Date: Fri, 27 Jul 2012 15:08:07 -0400 Message-ID: <5012E717.9070808@tmr.com> References: <501078B2.8070707@familyross.net> <501096C3.5060700@turmel.org> <5010A386.4080209@familyross.net> <5010CEFF.5030606@familyross.net> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5010CEFF.5030606@familyross.net> Sender: linux-raid-owner@vger.kernel.org To: Kevin Ross , Linux RAID , Linux Kernel mailing List List-Id: linux-raid.ids Kevin Ross wrote: > >>> >>>> unused devices: >>>> >>>> # cat /proc/sys/dev/raid/speed_limit_min >>>> 10000 >>> MD is unable to reach its minimum rebuild rate while other system >>> activity is ongoing. You might want to lower this number to see if that >>> gets you out of the stalls. >>> >>> Or temporarily shut down mythtv. >> >> I will try lowering those numbers next time this happens, which will probably >> be within the next day or two. That's about how often this happens. > > Unfortunately, it has happened again, with speeds at near zero. > > # cat /proc/mdstat > Personalities : [raid6] [raid5] [raid4] > md0 : active raid6 sdh1[0] sdd1[9] sde1[10] sdb1[6] sdi1[7] sdc1[4] sdf1[3] > sdg1[8] sdj1[1] > 6837311488 blocks super 1.2 level 6, 512k chunk, algorithm 2 [9/9] > [UUUUUUUUU] > [=>...................] resync = 8.3% (81251712/976758784) > finish=1057826.4min speed=14K/sec > > unused devices: > > atop doesn't show ANY activity on the raid device or the individual drives. > http://img687.imageshack.us/img687/2913/screenshotfrom201207252.png > > Also, I tried writing to a test file with the following command, and it hangs. > I let it go for about 30 minutes, with no change. > > # dd if=/dev/zero of=test bs=1M count=1 > > dmesg only reports hung tasks. It doesn't report any other problems. Here's my > dmesg output: > http://pastebin.ca/2174778 > > I'm going to try rebooting into single user mode, and see if the rebuild > succeeds without stalling. > Have you set the io scheduler to deadline on all members of the array? That's kind of "job one" on older kernels. -- Bill Davidsen "We have more to fear from the bungling of the incompetent than from the machinations of the wicked." - from Slashdot