sudo mdadm -D /dev/md0 
/dev/md0:
        Version : 00.90
  Creation Time : Sat Jun 28 19:32:07 2008
     Raid Level : linear
     Array Size : 2930297856 (2794.55 GiB 3000.63 GB)
   Raid Devices : 4
  Total Devices : 4
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Sun Apr 26 19:40:05 2009
          State : active
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0

       Rounding : 64K

           UUID : 5f2f58bc:25b44d62:9b8c7f44:2e4a8283 (local to host babyjesus)
         Events : 0.59

    Number   Major   Minor   RaidDevice State
       0       8        0        0      active sync   /dev/sda
       1       8       16        1      active sync   /dev/sdb
       2       8       32        2      active sync   /dev/sdc
       3       8       48        3      active sync   /dev/sdd



sudo mdadm --examine /dev/sd[abcd]
/dev/sda:
          Magic : a92b4efc
        Version : 00.90.00
           UUID : 5f2f58bc:25b44d62:9b8c7f44:2e4a8283 (local to host babyjesus)
  Creation Time : Sat Jun 28 19:32:07 2008
     Raid Level : linear
   Raid Devices : 4
  Total Devices : 4
Preferred Minor : 0

    Update Time : Sun Apr 26 19:40:05 2009
          State : active
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0
       Checksum : b5ed3a66 - correct
         Events : 59

       Rounding : 64K

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

   0     0       8        0        0      active sync   /dev/sda
   1     1       8       16        1      active sync   /dev/sdb
   2     2       8       32        2      active sync   /dev/sdc
   3     3       8       48        3      active sync   /dev/sdd
/dev/sdb:
          Magic : a92b4efc
        Version : 00.90.00
           UUID : 5f2f58bc:25b44d62:9b8c7f44:2e4a8283 (local to host babyjesus)
  Creation Time : Sat Jun 28 19:32:07 2008
     Raid Level : linear
   Raid Devices : 4
  Total Devices : 4
Preferred Minor : 0

    Update Time : Sun Apr 26 19:40:05 2009
          State : active
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0
       Checksum : b5ed3a78 - correct
         Events : 59

       Rounding : 64K

      Number   Major   Minor   RaidDevice State
this     1       8       16        1      active sync   /dev/sdb

   0     0       8        0        0      active sync   /dev/sda
   1     1       8       16        1      active sync   /dev/sdb
   2     2       8       32        2      active sync   /dev/sdc
   3     3       8       48        3      active sync   /dev/sdd
/dev/sdc:
          Magic : a92b4efc
        Version : 00.90.00
           UUID : 5f2f58bc:25b44d62:9b8c7f44:2e4a8283 (local to host babyjesus)
  Creation Time : Sat Jun 28 19:32:07 2008
     Raid Level : linear
   Raid Devices : 4
  Total Devices : 4
Preferred Minor : 0

    Update Time : Sun Apr 26 19:40:05 2009
          State : active
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0
       Checksum : b5ed3a8a - correct
         Events : 59

       Rounding : 64K

      Number   Major   Minor   RaidDevice State
this     2       8       32        2      active sync   /dev/sdc

   0     0       8        0        0      active sync   /dev/sda
   1     1       8       16        1      active sync   /dev/sdb
   2     2       8       32        2      active sync   /dev/sdc
   3     3       8       48        3      active sync   /dev/sdd
/dev/sdd:
          Magic : a92b4efc
        Version : 00.90.00
           UUID : 5f2f58bc:25b44d62:9b8c7f44:2e4a8283 (local to host babyjesus)
  Creation Time : Sat Jun 28 19:32:07 2008
     Raid Level : linear
   Raid Devices : 4
  Total Devices : 4
Preferred Minor : 0

    Update Time : Sun Apr 26 19:40:05 2009
          State : active
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0
       Checksum : b5ed3a9c - correct
         Events : 59

       Rounding : 64K

      Number   Major   Minor   RaidDevice State
this     3       8       48        3      active sync   /dev/sdd

   0     0       8        0        0      active sync   /dev/sda
   1     1       8       16        1      active sync   /dev/sdb
   2     2       8       32        2      active sync   /dev/sdc
   3     3       8       48        3      active sync   /dev/sdd