Hotplug
From Linux Raid Wiki
(Difference between revisions)
(→mdadm versions < 3.1.2) |
(→mdadm versions < 3.1.2) |
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=mdadm versions < 3.1.2= | =mdadm versions < 3.1.2= | ||
| − | Let's have | + | Let's have the following RAID configuration: |
| − | If we hot-unplugged the disk /dev/sda, the /proc/mdstat | + | # cat /proc/mdstat |
| + | Personalities : [raid1] | ||
| + | md0 : active raid1 sda1[0] sdb1[1] | ||
| + | 3903680 blocks [2/2] [UU] | ||
| + | |||
| + | md1 : active raid1 sda2[0] sdb2[1] | ||
| + | 224612672 blocks [2/2] [UU] | ||
| + | |||
| + | If we hot-unplugged the disk /dev/sda, the /proc/mdstat will show: | ||
# cat /proc/mdstat | # cat /proc/mdstat | ||
| Line 12: | Line 20: | ||
md0 : active raid1 sda1'''[2](F)''' sdb1[1] | md0 : active raid1 sda1'''[2](F)''' sdb1[1] | ||
3903680 blocks [2/1] [_U] | 3903680 blocks [2/1] [_U] | ||
| − | + | ||
md1 : active raid1 sda2[0] sdb2[1] | md1 : active raid1 sda2[0] sdb2[1] | ||
224612672 blocks [2/2] [UU] | 224612672 blocks [2/2] [UU] | ||
Revision as of 07:14, 15 April 2010
HW issues of the disk hotplugging are described in the Hotswap chapter of theHardware issues page.
The Linux RAID supports hotplug operations fully from Hot-unplug branch of the mdadm version 3.1.2.
mdadm versions < 3.1.2
Let's have the following RAID configuration:
# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sda1[0] sdb1[1]
3903680 blocks [2/2] [UU]
md1 : active raid1 sda2[0] sdb2[1]
224612672 blocks [2/2] [UU]
If we hot-unplugged the disk /dev/sda, the /proc/mdstat will show:
# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sda1[2](F) sdb1[1]
3903680 blocks [2/1] [_U]
md1 : active raid1 sda2[0] sdb2[1]
224612672 blocks [2/2] [UU]
We see that sda1 has role [2]. Since RAID1 needs only 2 components - [0] and [1], the [2] means "Spare disk". And it is (F)ailed.
What we can do is remove the failed disk:
# mdadm /dev/md3 --fail detached --remove detached mdadm: hot removed 8:1
mdadm versions > 3.1.2
(to be finished)
