nas ~ # mdadm -D /dev/md3
/dev/md3:
        Version : 1.2
  Creation Time : Fri Aug 24 04:23:04 2012
     Raid Level : raid5
     Array Size : 4315210752 (4115.31 GiB 4418.78 GB)
  Used Dev Size : 1438403584 (1371.77 GiB 1472.93 GB)
   Raid Devices : 4
  Total Devices : 4
    Persistence : Superblock is persistent

    Update Time : Sun Dec  1 19:08:30 2013
          State : clean 
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 512K

           Name : localhost.localdomain:3
           UUID : cf205a21:16cfbf89:1b7442b4:130edcb3
         Events : 42942

    Number   Major   Minor   RaidDevice State
       0       8        4        0      active sync   /dev/sda4
       4       8       35        1      active sync   /dev/sdc3
       3       8       51        2      active sync   /dev/sdd3
       5       8       19        3      active sync   /dev/sdb3