# cat /proc/mdstat
Personalities : [raid5] [raid4]
md1 : active raid5 sda4[0] sdd4[2]
      439008000 blocks level 5, 64k chunk, algorithm 2 [3/2] [U_U]

md0 : active raid5 sdd3[1] sda3[0]
      48837376 blocks level 5, 64k chunk, algorithm 2 [3/2] [UU_]

=======================

# mdadm -D /dev/md0
/dev/md0:
        Version : 00.90.03
  Creation Time : Wed Sep 20 18:32:57 2006
     Raid Level : raid5
     Array Size : 48837376 (46.57 GiB 50.01 GB)
    Device Size : 24418688 (23.29 GiB 25.00 GB)
   Raid Devices : 3
  Total Devices : 2
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Mon Oct  9 17:39:22 2006
          State : clean, degraded
 Active Devices : 2
Working Devices : 2
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : 08644c7f:b05141dd:2b2b9aa7:f3b74baf
         Events : 0.10006

    Number   Major   Minor   RaidDevice State
       0       8        3        0      active sync   /dev/sda3
       1       8       51        1      active sync   /dev/sdd3
       2       0        0        2      removed