So /dev/sdb3 was the device that failed and the number of events on
the remaining two devices is the same. So to start the array you
should be able run
mdadm --assemble /dev/md0 --uuid=84087667:ce58ade4:68147ff7:77e6d0fd
mdadm: /dev/md0 has been started with 2 drives (out of 3).
cat /proc/mdstat
assuming that this shows the state as "clean, degraded" you should
then be able to add back in the failed device.
mdadm --manage /dev/md0 --add /dev/sdb3
mdadm: re-added /dev/loop0
cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 loop0[3] loop1[1] loop2[2]
2097024 blocks level 5, 64k chunk, algorithm 2 [3/2] [_UU]
[====>................] recovery = 23.9% (251384/1048512) finish=2.3min speed=5631K/sec
unused devices: <none>
Hope this helps.
btw as always if you have lots of spare disk then it's a good idea to
take copies of the disks/partitions first.
Stan
On Wed, Apr 28, 2010 at 07:26:55PM +0100, James Courtier-Dutton wrote:
> Hi,
>
> Below is the output from the mdadm -E option for my 3 partitions in a
> raid array.
> As you can see, each drive disagrees with the state of the array.
> No matter what I try, I cannot seem to get the array back in sync again.
> One sees this:
> this 0 8 19 0 active sync /dev/sdb3
> 0 0 8 19 0 active sync /dev/sdb3
> 1 1 8 35 1 active sync /dev/sdc3
> 2 2 8 51 2 active sync /dev/sdd3
>
> this 1 8 35 1 active sync /dev/sdc3
> 0 0 0 0 0 removed
> 1 1 8 35 1 active sync /dev/sdc3
> 2 2 8 51 2 active sync /dev/sdd3
>
> this 1 8 35 1 active sync /dev/sdc3
> 0 0 0 0 0 removed
> 1 1 8 35 1 active sync /dev/sdc3
> 2 2 8 51 2 active sync /dev/sdd3
>
> How do I get them all to agree which one has been removed?
> I get errors like, when I try to remove /dev/sdb3 from the array it
> does not let me, saying it is already removed.
> when I try to add it, it says the drive is already in use.
>
> Kind Regards
>
> James
>
>
> root@quad:/home/raid# mdadm -E /dev/sdb3
> /dev/sdb3:
> Magic : a92b4efc
> Version : 00.90.00
> UUID : 84087667:ce58ade4:68147ff7:77e6d0fd (local to host quad)
> Creation Time : Fri Apr 16 17:44:30 2010
> Raid Level : raid5
> Used Dev Size : 195502912 (186.45 GiB 200.19 GB)
> Array Size : 391005824 (372.89 GiB 400.39 GB)
> Raid Devices : 3
> Total Devices : 3
> Preferred Minor : 3
>
> Update Time : Fri Apr 16 18:50:30 2010
> State : clean
> Active Devices : 3
> Working Devices : 3
> Failed Devices : 0
> Spare Devices : 0
> Checksum : 7ec12025 - correct
> Events : 20
>
> Layout : left-symmetric
> Chunk Size : 64K
>
> Number Major Minor RaidDevice State
> this 0 8 19 0 active sync /dev/sdb3
>
> 0 0 8 19 0 active sync /dev/sdb3
> 1 1 8 35 1 active sync /dev/sdc3
> 2 2 8 51 2 active sync /dev/sdd3
> root@quad:/home/raid# mdadm -E /dev/sdc3
> /dev/sdc3:
> Magic : a92b4efc
> Version : 00.90.00
> UUID : 84087667:ce58ade4:68147ff7:77e6d0fd (local to host quad)
> Creation Time : Fri Apr 16 17:44:30 2010
> Raid Level : raid5
> Used Dev Size : 195502912 (186.45 GiB 200.19 GB)
> Array Size : 391005824 (372.89 GiB 400.39 GB)
> Raid Devices : 3
> Total Devices : 2
> Preferred Minor : 3
>
> Update Time : Wed Apr 28 17:56:51 2010
> State : clean
> Active Devices : 2
> Working Devices : 2
> Failed Devices : 0
> Spare Devices : 0
> Checksum : 7ed0e5a0 - correct
> Events : 32
>
> Layout : left-symmetric
> Chunk Size : 64K
>
> Number Major Minor RaidDevice State
> this 1 8 35 1 active sync /dev/sdc3
>
> 0 0 0 0 0 removed
> 1 1 8 35 1 active sync /dev/sdc3
> 2 2 8 51 2 active sync /dev/sdd3
> root@quad:/home/raid# mdadm -E /dev/sdd3
> /dev/sdd3:
> Magic : a92b4efc
> Version : 00.90.00
> UUID : 84087667:ce58ade4:68147ff7:77e6d0fd (local to host quad)
> Creation Time : Fri Apr 16 17:44:30 2010
> Raid Level : raid5
> Used Dev Size : 195502912 (186.45 GiB 200.19 GB)
> Array Size : 391005824 (372.89 GiB 400.39 GB)
> Raid Devices : 3
> Total Devices : 2
> Preferred Minor : 3
>
> Update Time : Wed Apr 28 17:56:51 2010
> State : clean
> Active Devices : 2
> Working Devices : 2
> Failed Devices : 0
> Spare Devices : 0
> Checksum : 7ed0e5b2 - correct
> Events : 32
>
> Layout : left-symmetric
> Chunk Size : 64K
>
> Number Major Minor RaidDevice State
> this 2 8 51 2 active sync /dev/sdd3
>
> 0 0 0 0 0 removed
> 1 1 8 35 1 active sync /dev/sdc3
> 2 2 8 51 2 active sync /dev/sdd3
> root@quad:/home/raid#
> root@quad:/home/raid# exit
> exit
>
> --
> Please post to: Hampshire@???
> Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire
> LUG URL: http://www.hantslug.org.uk
> --------------------------------------------------------------
