[CentOS] Re: Rebuilding Raid 1

Mace Eliason meliason at shaw.ca
Tue May 2 05:13:09 UTC 2006

I think the reason for the partitions not being on the same drive is 
because the old drive is the bootable drive and I changed the scsi ids 
of the drives to get it to work.   I think it is using sba for the boot 
but centos is on sbb. 

I just need to make sure that the sync happens so that the info on sbb 
is what is synced.  The info on sba is 1 month old this I have confirmed 
by mounting sba3 and looking at the dates of the last emails received on 
the server  I couldn't mount sdb3 because it is the active partition.

So from what your saying below running mdadm as you have shown will it 
copy the good info on sdb to sda?

I have to have this server ready for 7am or we will loose this 
contract.  I can't believe I have spend all day on this.

Thanks for the help

If I copy over the wrong info they will lose 1 months worth of emails.


Les Mikesell wrote:
> On Mon, 2006-05-01 at 23:18, Mace Eliason wrote:
>> Personalities : [raid1]
>> md1 : active raid1 sdb2[0]
>>           2048192 blocks [2/1] [U_]
>> md2:  active raid1 sdb3[0]
>>           15623104 blocks [2/1] [U_]
>> md0:  active raid1 sda1[1]
>>           104320 blocks [2/1] [_U]
> That tells you that your raid devices were built with
> 2 partitions and now only have one active.  It shows
> which member is active - note that they aren't all
> on the same drive.  Assuming you have matching
> partitions on the other drive (do an 'fdisk -l' to
> make sure) and are sure the correct version is
> running now:
> mdadm --add /dev/md0 /dev/sdb1
> mdadm --add /dev/md1 /dev/sda2
> mdadm --add /dev/md2 /dev/sda3
> 'cat /proc/mdstat' will show the re-sync progress. Don't
> reboot until the resync is complete and you see [UU] on
> all devices.  When they have all completed, if you
> reboot cleanly the md devices will come up with both
> partitions active (but you don't have to reboot unless
> you want to test it).

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