From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Sanders Subject: Re: stuck tasks Date: Mon, 12 Apr 2010 14:02:21 +0100 Message-ID: References: <4BC2FE9E.9040802@shiftmail.org> <4BC316EC.9040808@shiftmail.org> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7Bit Return-path: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids MRK wrote: > > Mistake of mine, but I might have gotten the right answer by chance > I had read resyncing but you wrote rsyncing. > But you were in fact also resyncing from what you write below: Not at the time of crash! Sorry for the confusion. This happened on reboot as the drive didn't properly unmount. > Resync speed is indeed quite low if you confirm there is no other disk > activity. It's not doing anything else on that drive. I think it would be faster but the option CONFIG_MULTICORE_RAID456 was switched on in this kernel, so there are lots of async processes fighting each other (190 of them on this system). > Instead if rsync is also running, you need to stop that one to have a > proper resync speed measurement (to compute the value to be entered into > sync_speed_max as per my previous email). > Do you have disk write caches activated? See that with tw_cli (3ware's > CLI) How much is /sys/block/md{n}/md/stripe_cache_size? Pump it up to > 32768. The disk write caches are on. The raid device is fast if you do bonnie tests to them (>100MBs). I tried the strip_cache_size option. The speed stays around 10 MB/s on this system. It looks like the sync speed has slowed down a lot since the sync started. Jeremy