How do I mount one half of a software Raid-1?

Question

I have one disk out of a system which used LVM on top of software RAID-1. I can't seem to mount the partition.

Here is the output of mdadm --examine

mdadm --examine /dev/sdd3
/dev/sdd3:
          Magic : a92b4efc
        Version : 00.90.00
           UUID : 796cb574:f1263d29:de01a688:bcce49e1
  Creation Time : Mon May  3 20:56:55 2010
     Raid Level : raid1
  Used Dev Size : 973828096 (928.71 GiB 997.20 GB)
     Array Size : 973828096 (928.71 GiB 997.20 GB)
   Raid Devices : 2
  Total Devices : 2
Preferred Minor : 0

    Update Time : Sun Sep  5 14:42:20 2010
          State : active
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0
       Checksum : 80fcf82e - correct
         Events : 0.29


      Number   Major   Minor   RaidDevice State
this     0       8        3        0      active sync   /dev/sda3

   0     0       8        3        0      active sync   /dev/sda3
   1     1       8       19        1      active sync   /dev/sdb3

How can I mount this and get the data off it?

Answer 1

You should be able to get at this with 'mdadm --assemble /dev/md1 --run /dev/sdd3' the --run is required, as normally mdadm will abort if there are missing member disks. Then you can do vgscan and you should be able to mount the logical volumes.

Answer 2

To make the VG available, you need to do the following:

vgchange --available -y vgname

Then you should be able to lvscan and mount accordingly.