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.....
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