From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: nonzero mismatch_cnt with no earlier error Date: Sun, 25 Feb 2007 15:02:42 -0500 Message-ID: <45E1EB62.40106@tmr.com> References: <45DF859B.2050108@eyal.emu.id.au> <45DFE217.3020703@eyal.emu.id.au> <1172310529.4431.9.camel@merlin> <45E01D01.4080205@tls.msk.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Justin Piszcz Cc: Michael Tokarev , Jason Rainforest , Eyal Lebedinsky , linux-raid list List-Id: linux-raid.ids Justin Piszcz wrote: > > > On Sat, 24 Feb 2007, Michael Tokarev wrote: > >> Jason Rainforest wrote: >>> I tried doing a check, found a mismatch_cnt of 8 (7*250Gb SW RAID5, >>> multiple controllers on Linux 2.6.19.2, SMP x86-64 on Athlon64 X2 4200 >>> +). >>> >>> I then ordered a resync. The mismatch_cnt returned to 0 at the start of >> >> As pointed out later it was repair, not resync. >> >>> the resync, but around the same time that it went up to 8 with the >>> check, it went up to 8 in the resync. After the resync, it still is >>> 8. I >>> haven't ordered a check since the resync completed. >> >> As far as I understand, repair will do the same as check does, but ALSO >> will try to fix the problems found. So the number in mismatch_cnt after >> a repair will indicate the amount of mismatches found _and fixed_ >> >> /mjt >> > > That is what I thought too (I will have to wait until I get another > mismatch to verify), but FYI-- > > Yesterday I had 512 mismatches for my swap partition (RAID1) after I > ran the check. > > I ran repair. > > I catted the mismatch_cnt again, still 512. > > I re-ran the check, back to 0. AFAIK the "repair" action will give you a count of the repairs it does, and will fail a drive if a read does not succeed after the sector is rewritten. That's the way I read it, and the way it seems to work. -- bill davidsen CTO TMR Associates, Inc Doing interesting things with small computers since 1979