Just a quicky reference on removing a drive for those of you using mdadm.
Check the status of a raid device
[[email protected] ~]# mdadm --detail /dev/md10
/dev/md10:
Version : 1.2
Creation Time : Sat Jul 2 13:56:38 2011
Raid Level : raid1
Array Size : 26212280 (25.00 GiB 26.84 GB)
Used Dev Size : 26212280 (25.00 GiB 26.84 GB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Sat Jul 2 13:56:47 2011
State : clean, resyncing
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Rebuild Status : 10% complete
Name : bcane.virtuals.local:10 (local to host bcane.virtuals.local)
UUID : 10a96ed5:92dc48e6:04b2bf43:3539e089
Events : 1
Number Major Minor RaidDevice State
0 8 33 0 active sync /dev/sdc1
1 8 49 1 active sync /dev/sdd1
In order to remove a drive it must first be marked as faulty. A drive can be marked as faulty either through a failure or if you want to manually mark a drive as faulty you can use the -f/--fail flag.
[[email protected] ~]# mdadm /dev/md10 -f /dev/sdc1
mdadm: set /dev/sdc1 faulty in /dev/md10
[[email protected] ~]# mdadm --detail /dev/md10
/dev/md10:
Version : 1.2
Creation Time : Sat Jul 2 13:56:38 2011
Raid Level : raid1
Array Size : 26212280 (25.00 GiB 26.84 GB)
Used Dev Size : 26212280 (25.00 GiB 26.84 GB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Sat Jul 2 14:00:18 2011
State : active, degraded
Active Devices : 1
Working Devices : 1
Failed Devices : 1
Spare Devices : 0
Name : bcane.virtuals.local:10 (local to host bcane.virtuals.local)
UUID : 10a96ed5:92dc48e6:04b2bf43:3539e089
Events : 19
Number Major Minor RaidDevice State
0 0 0 0 removed
1 8 49 1 active sync /dev/sdd1
0 8 33 - faulty spare /dev/sdc1
Now that the drive is marked as failed/faulty you can remove it using the -r/--remove flag.
[[email protected] ~]# mdadm /dev/md10 -r /dev/sdc1
mdadm: hot removed /dev/sdc1 from /dev/md10
[[email protected] ~]# mdadm --detail /dev/md10
/dev/md10:
Version : 1.2
Creation Time : Sat Jul 2 13:56:38 2011
Raid Level : raid1
Array Size : 26212280 (25.00 GiB 26.84 GB)
Used Dev Size : 26212280 (25.00 GiB 26.84 GB)
Raid Devices : 2
Total Devices : 1
Persistence : Superblock is persistent
Update Time : Sat Jul 2 14:02:04 2011
State : active, degraded
Active Devices : 1
Working Devices : 1
Failed Devices : 0
Spare Devices : 0
Name : bcane.virtuals.local:10 (local to host bcane.virtuals.local)
UUID : 10a96ed5:92dc48e6:04b2bf43:3539e089
Events : 20
Number Major Minor RaidDevice State
0 0 0 0 removed
1 8 49 1 active sync /dev/sdd1
If you want to re-add the device you can do so with the -a flag.
[[email protected] ~]# mdadm /dev/md10 -a /dev/sdc1
mdadm: re-added /dev/sdc1
[[email protected] ~]# mdadm --detail /dev/md10
/dev/md10:
Version : 1.2
Creation Time : Sat Jul 2 13:56:38 2011
Raid Level : raid1
Array Size : 26212280 (25.00 GiB 26.84 GB)
Used Dev Size : 26212280 (25.00 GiB 26.84 GB)
Raid Devices : 2
Total Devices : 2
Persistence : Superblock is persistent
Update Time : Sat Jul 2 18:02:21 2011
State : clean, degraded, recovering
Active Devices : 1
Working Devices : 2
Failed Devices : 0
Spare Devices : 1
Rebuild Status : 4% complete
Name : bcane.virtuals.local:10 (local to host bcane.virtuals.local)
UUID : 10a96ed5:92dc48e6:04b2bf43:3539e089
Events : 23
Number Major Minor RaidDevice State
0 8 33 0 spare rebuilding /dev/sdc1
1 8 49 1 active sync /dev/sdd1
One thing to keep an eye out for is that you need to specify the raid device when running these commands. If they are performed without specifying the raid device the flags take on a new meaning.
Recently Benjamin published his first book; Red Hat Enterprise Linux Troubleshooting Guide. In addition to writing, he has several Open Source projects focused on making Ops easier. These projects include Automatron, a project enabling auto-healing infrastructure for the masses.
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