Additional info (how many RAID arrays do I have??):
# mdadm -D /dev/md3
/dev/md3:
Version : 00.90
Creation Time : Sat Mar 19 22:53:25 2011
Raid Level : raid1
Array Size : 185151360 (176.57 GiB 189.59 GB)
Used Dev Size : 185151360 (176.57 GiB 189.59 GB)
Raid Devices : 2
Total Devices : 2
Preferred Minor : 3
Persistence : Superblock is persistent
Update Time : Thu Apr 28 21:09:12 2011
State : clean, resyncing
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Rebuild Status : 38% complete
UUID : 1b3668a3:4b6c5593:3d186b3c:53958f34
Events : 0.15
Number Major Minor RaidDevice State
0 8 6 0 active sync /dev/sda6
1 8 22 1 active sync /dev/sdb6