From mboxrd@z Thu Jan 1 00:00:00 1970 From: Justin Piszcz Subject: Re: how to deal with continuously getting more errors? Date: Sat, 14 Jul 2007 17:03:22 -0400 (EDT) Message-ID: References: <98d279bf0707141115m14308e64s50f6517b2e1aef5c@mail.gmail.com> Mime-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Return-path: In-Reply-To: <98d279bf0707141115m14308e64s50f6517b2e1aef5c@mail.gmail.com> Sender: linux-raid-owner@vger.kernel.org To: jeff stern Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids On Sat, 14 Jul 2007, jeff stern wrote: > hi, everyone.. i have a problem. > > SUMMARY > > i've got a linux software RAID1 setup, with 2 SATA drives (/dev/sdf1, > /dev/sdg1) set up to be /dev/md0. these 2 drives together hold my > /home directories. the / and / partitions are on another drive, a > standard parallel IDE (/dev/hda). (I can provide more hardware > information if someone needs it). > > the problem is that new errors (mismatch_cnt discrepancies) between > the two disks keep coming up. weekly. even daily, and i dont know what > to do, or how to handle it. > > How many mismatch_cnts between two almost-new drives running in a > healthy RAID1 array should one expect in a year? in a month? a day? > > And more importantly, What do i do now? > > EXTENDED DESCRIPTION OF PROBLEM > > i first noticed this problem when i downloaded the fedora core 7 .iso, > and did a checksum on it, and it didn't match. with a little more > investigating, i found that i could make a copy of any large file on > disk, and its copy would sometimes match, sometimes not. > > here is a typical session: > ------------------------------------------------------------------------------------------ > $ cp F-7-i386-DVD.iso F.iso > $ cmp F-7-i386-DVD.iso F.iso > F-7-i386-DVD.iso F.iso differ: byte 1033827385, line 3789612 > $ cmp F-7-i386-DVD.iso F.iso > $ cmp F-7-i386-DVD.iso F.iso > F-7-i386-DVD.iso F.iso differ: byte 1033827385, line 3789612 > $ cmp F-7-i386-DVD.iso F.iso > F-7-i386-DVD.iso F.iso differ: byte 8870221, line 37265 > $ cmp F-7-i386-DVD.iso F.iso > F-7-i386-DVD.iso F.iso differ: byte 8870221, line 37265 > $ _ > ------------------------------------------------------------------------------------------ Something sounds very strange here, I have a script that runs the 'check' once a week for my RAID1 partitions and it is generally 0 every time, except for the swap parition (occasionally)- which Neil has mentioned-- is normal. You bringup a lot of good points though; however, I am not sure why you are experiencing so many mismatches..... Justin.