[smiler@fs ~]$ cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md0 : active raid5 sde[4](S) sdd[3] sdb[0] sdc[1]
      3907026688 blocks super 1.2 level 5, 128k chunk, algorithm 2 [3/3] [UUU]

unused devices: <none>

[smiler@fs ~]$ sudo mdadm --detail /dev/md0
Password:
/dev/md0:
        Version : 1.2
  Creation Time : Sun Oct 10 14:09:55 2010
     Raid Level : raid5
     Array Size : 3907026688 (3726.03 GiB 4000.80 GB)
  Used Dev Size : 1953513344 (1863.02 GiB 2000.40 GB)
   Raid Devices : 3
  Total Devices : 4
    Persistence : Superblock is persistent

    Update Time : Fri Oct  7 13:04:53 2011
          State : clean
 Active Devices : 3
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 1

         Layout : left-symmetric
     Chunk Size : 128K

           Name : fs:0  (local to host fs)
           UUID : 4f01fe5c:c3afccfd:c69b82d2:b49f44a0
         Events : 9892

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

       4       8       64        -      spare   /dev/sde



smiler@eof:~$ cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4]
md1 : active raid5 sdh[5] sdg[4] sdf[3] sde[2] sdd[1] sdc[0]
      9767572480 blocks level 5, 64k chunk, algorithm 2 [6/6] [UUUUUU]

md0 : active raid5 sda[0] sdj[4] sdl[3] sdi[1]
      3907049984 blocks level 5, 64k chunk, algorithm 2 [5/4] [UU_UU]

unused devices: <none>

smiler@eof:~$ sudo mdadm --detail /dev/md0
[sudo] password for smiler:
/dev/md0:
        Version : 00.90
  Creation Time : Fri Feb  4 19:13:45 2011
     Raid Level : raid5
     Array Size : 3907049984 (3726.05 GiB 4000.82 GB)
  Used Dev Size : 976762496 (931.51 GiB 1000.20 GB)
   Raid Devices : 5
  Total Devices : 4
Preferred Minor : 0
    Persistence : Superblock is persistent

    Update Time : Fri Oct  7 13:00:08 2011
          State : clean, degraded
 Active Devices : 4
Working Devices : 4
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : 4c9911ae:2792bfaa:f965a3e8:1a55b85c (local to host eof)
         Events : 0.119520

    Number   Major   Minor   RaidDevice State
       0       8        0        0      active sync   /dev/sda
       1       8      128        1      active sync   /dev/sdi
       2       0        0        2      removed
       3       8      176        3      active sync   /dev/sdl
       4       8      144        4      active sync   /dev/sdj

smiler@eof:~$ sudo mdadm --detail /dev/md1
/dev/md1:
        Version : 00.90
  Creation Time : Tue Jul  5 22:31:27 2011
     Raid Level : raid5
     Array Size : 9767572480 (9315.08 GiB 10001.99 GB)
  Used Dev Size : 1953514496 (1863.02 GiB 2000.40 GB)
   Raid Devices : 6
  Total Devices : 6
Preferred Minor : 1
    Persistence : Superblock is persistent

    Update Time : Fri Oct  7 13:36:27 2011
          State : clean
 Active Devices : 6
Working Devices : 6
 Failed Devices : 0
  Spare Devices : 0

         Layout : left-symmetric
     Chunk Size : 64K

           UUID : 018f7b26:20196348:f965a3e8:1a55b85c (local to host eof)
         Events : 0.177998

    Number   Major   Minor   RaidDevice State
       0       8       32        0      active sync   /dev/sdc
       1       8       48        1      active sync   /dev/sdd
       2       8       64        2      active sync   /dev/sde
       3       8       80        3      active sync   /dev/sdf
       4       8       96        4      active sync   /dev/sdg
       5       8      112        5      active sync   /dev/sdh