Hello,

I'm using a software raid 1 (mirror) with mdadm and LVM volums. After a 
mainboard defect I have added the disks to the system and get an error:

        Version : 1.2
  Creation Time : Sat Oct 15 19:21:58 2011
     Raid Level : raid1
     Array Size : 1953513424 (1863.02 GiB 2000.40 GB)
  Used Dev Size : 1953513424 (1863.02 GiB 2000.40 GB)
   Raid Devices : 2
  Total Devices : 1
    Persistence : Superblock is persistent

    Update Time : Fri Mar 16 12:24:44 2012
          State : clean, degraded
 Active Devices : 1
Working Devices : 1
 Failed Devices : 0
  Spare Devices : 0

           Name : myhost:0  (local to host myhost)
           UUID : 30c70170:515705d8:eb55419b:2b7775c0
         Events : 87

    Number   Major   Minor   RaidDevice State
       0       8       48        0      active sync   /dev/sdd
       1       0        0        1      removed

The other md device (md1) is consistent:

        Version : 0.90
  Creation Time : Thu Apr  9 22:40:39 2009
     Raid Level : raid1
     Array Size : 976759936 (931.51 GiB 1000.20 GB)
  Used Dev Size : 976759936 (931.51 GiB 1000.20 GB)
   Raid Devices : 2
  Total Devices : 2
Preferred Minor : 1
    Persistence : Superblock is persistent

    Update Time : Fri Mar 16 12:29:30 2012
          State : clean
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

           UUID : 5493efe7:ace56468:bc3ff3b1:b66df632
         Events : 0.406

    Number   Major   Minor   RaidDevice State
       0       8       17        0      active sync   /dev/sdb1
       1       8       33        1      active sync   /dev/sdc1

Under the /dev both disks for the first array are exists (second also):

md1 : active raid1 sdb1[0] sdc1[1]
      976759936 blocks [2/2] [UU]

md127 : active (auto-read-only) raid1 sdd[0]
      1953513424 blocks super 1.2 [2/1] [U_]

working array (/dev/sdb and sdc)
ata-WDC_WD1002FBYS-01A6B0_WD-WMATV0302289
ata-WDC_WD1002FBYS-01A6B0_WD-WMATV0302289-part1
ata-WDC_WD1002FBYS-01A6B0_WD-WMATV0349410
ata-WDC_WD1002FBYS-01A6B0_WD-WMATV0349410-part1

and non-working array
ata-Hitachi_HDS723020BLA642_MN1220F326YS3D
ata-Hitachi_HDS723020BLA642_MN1220F327TVTD

Can I check the removed disk on the first array and can I add it�, if 
the disk is okay, to the array again?
I have mounted the LVM group and I can see my data, so I think one disk 
works correct.

Thanks a lot

Phil