Re: raid problem

[Andre Majorel <aym-naibed@teaser.fr>]

On 2013-11-29 23:43 +0100, François Patte wrote:

> I have a problem with 2 raid arrays: I have 2 disks (sdc and sdd) in
> raid1 arrays.
> 
> One disk (sdc) failed and I replaced it by a new one. Copying the
> partition table from sdd disk using sfdisk:
> 
> sfdisk -d /dev/sdd | sfdisk /dev/sdc
> 
> then I "added" the 2 partitions (sdc1 and sdc3) to the arrays md0 and md1:
> 
> mdadm --add /dev/md0 /dev/sdc1
> 
> mdadm --add /dev/md1 /dev/sdc3
> 
> There were no problem with the md0 array:
> 
> 
> cat /proc/mdstat gives:
> 
> md0 : active raid1 sdc1[1] sdd1[0]
>       1052160 blocks [2/2] [UU]
> 
> 
> But for the md1 array, I get:
> 
> md1 : active raid1 sdc3[2](S) sdd3[0]
>       483138688 blocks [2/1] [U_]
>
> What is the problem? And how can I recover a correct md1 array?

The root of your problem would be that /dev/sdc3 is considered
spare, not active. Not sure why.

Guess #1 : before physically changing the disks, you forgot
  mdadm /dev/md1 --fail   /dev/sdc3
  mdadm /dev/md1 --remove /dev/sdc3

Guess #2 : maybe there were I/O errors during the add. How far
did the sync go ? Run smartctl -d ata -A /dev/sdc3 and look for
non-zero raw values for Reallocated_Sector_Ct and
Current_Pending_Sector. What does badblocks /dev/sdc3 say ?

Guess #3 : it's a software hiccup and all /dev/sdc3 needs is to
be removed from /dev/md1 and re-added.

-- 
André Majorel <http://www.teaser.fr/~amajorel/>
bugs.debian.org, a spammer's favourite.