On Mon, Mar 16, 2009 at 4:27 AM, David Greaves <david@xxxxxxxxxxxx> wrote:
> I have a drive that has bad sectors. Lots of them.
>
> smartctl shows
> # 1 Short offline Completed: read failure 20% 530
> 1953520877
>
> A simple ddrescue to this part of the disk gets this:
>
> Mar 16 10:41:28 elm kernel: [ 8643.123397] sd 3:0:0:0: [sdd] 1953525168 512-byte
> hardware sectors (1000205 MB)
> <snip<>51/40:00:f0:5c:70/00:00:74:00:00/e0 Emask 0x9 (media error)
> Mar 16 10:41:29 elm kernel: [ 8644.190060] ata4.00: status: { DRDY ERR }
> Mar 16 10:41:29 elm kernel: [ 8644.190099] ata4.00: error: { UNC }
>
> and reports 30 or so errors.
>
>
> mdstat tells me:
> md0 : active raid5 sdd1[0] sdb1[2] sda1[1]
> 1953519872 blocks level 5, 64k chunk, algorithm 2 [3/3] [UUU]
>
> So sdd1 is in there.
>
> /dev/sdd1 is the full disk
>
Are you sure? Maybe I did the following math wrong, but it seems
there is a chance this bad region is outside the raid array.
/proc/mdstat says the array is 1953519872 blocks large which is
3907039744 sectors. For a three disk raid5 that means we are using
1953519872 sectors per disk. The failing sector of 1953520877 is 1005
sectors outside the array, probably 942 assuming partition 1 starts at
sector 63??
--
Dan
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