cat /proc/mdstat
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [raid10]
md1 : active raid1 sdb1[1]
4194240 blocks [2/1] [_U]
md3 : active raid1 sdb3[0]
970470016 blocks [2/1] [U_]
unused devices: <none>
-----------------------------------------------------------------------------
mdadm --detail /dev/md1
/dev/md1:
Version : 0.90
Creation Time : Tue Jun 28 21:37:54 2016
Raid Level : raid1
Array Size : 4194240 (4.00 GiB 4.29 GB)
Used Dev Size : 4194240 (4.00 GiB 4.29 GB)
Raid Devices : 2
Total Devices : 1
Preferred Minor : 1
Persistence : Superblock is persistent
Update Time : Mon Aug 8 15:47:07 2016
State : clean, degraded
Active Devices : 1
Working Devices : 1
Failed Devices : 0
Spare Devices : 0
UUID : 4878c265:cddfb861:1f51fb89:78ee93fe
Events : 0.315655
Number Major Minor RaidDevice State
0 0 0 0 removed
1 8 17 1 active sync /dev/sdb1
-----------------------------------------------------------------
mdadm --detail /dev/md3
/dev/md3:
Version : 0.90
Creation Time : Tue Jun 28 21:37:54 2016
Raid Level : raid1
Array Size : 970470016 (925.51 GiB 993.76 GB)
Used Dev Size : 970470016 (925.51 GiB 993.76 GB)
Raid Devices : 2
Total Devices : 1
Preferred Minor : 3
Persistence : Superblock is persistent
Update Time : Mon Aug 8 15:52:08 2016
State : active, degraded
Active Devices : 1
Working Devices : 1
Failed Devices : 0
Spare Devices : 0
UUID : 3719a2fe:5de22a92:1f51fb89:78ee93fe
Events : 0.5184968
Number Major Minor RaidDevice State
0 8 19 0 active sync /dev/sdb3
1 0 0 1 removed