1.
When do “more /proc/mdstat”, it
shows there is a missing drive
Personalities : [raid1]
md5 : active raid1 sda1[0]
3068288 blocks
[2/1] [U_]
md2 : active
raid1 sda2[0]
10241344 blocks
[2/1] [U_]
md1 : active
raid1 sda3[0]
10241344 blocks
[2/1] [U_]
md3 : active
raid1 sda6[0]
2048192 blocks
[2/1] [U_]
md4 : active
raid1 sda7[0]
128592192 blocks
[2/1] [U_]
md0 : active
raid1 sdb5[1] sda5[0]
2096384 blocks
[2/2] [UU]
2.
Do, “mdadm -D /dev/md1”, it
seems the missing unit has been removed
/dev/md1:
Version : 00.90.01
Creation Time : Wed Nov 2 03:44:57 2005
Raid Level : raid1
Array Size : 10241344 (9.77 GiB 10.49 GB)
Device Size : 10241344 (9.77 GiB 10.49 GB)
Raid Devices : 2
Total Devices : 1
Preferred Minor : 1
Persistence : Superblock is persistent
Update Time : Thu Mar 30
18:05:31 2006
State : clean, degraded
Active Devices : 1
Working Devices : 1
Failed Devices : 0
Spare Devices : 0
Number Major Minor
RaidDevice State
0 8 3 0 active sync /dev/sda3
1 0 0 -1 removed
UUID : 1d16a55f:71fed86c:5a198cc1:1db31dfa
Events : 0.1147282
3.
Add the missing unit back by “mdadm
/dev/md1 -a /dev/sdb3”
4.
Check again with “mdadm –D
/dev/md1”
Personalities : [raid1]
md5 : active raid1 sdb1[1]
sda1[0]
3068288 blocks [2/2] [UU]
md2 : active raid1 sdb2[1] sda2[0]
10241344 blocks [2/2] [UU]
md1 : active raid1 sdb3[1] sda3[0]
10241344 blocks [2/2] [UU]
md3 : active raid1 sdb6[1] sda6[0]
2048192 blocks [2/2] [UU]
md4 : active raid1 sdb7[1] sda7[0]
128592192 blocks [2/2] [UU]
md0 : active raid1 sdb5[1] sda5[0]
2096384 blocks [2/2] [UU]
unused devices: <none>
