February
1
Rebuilding raid with mdadm
Look at mdstat to see if a partition has been dropped from the array:
root@SERVER [~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sdb1[1] sda1[0]
521984 blocks [2/2] [UU]
md1 : active raid1 sda3[0]
483668864 blocks [2/1] [U_]
The [U_] shows that sdb3 is out of the array md1. To add /dev/sdb3 back into the array, we do the following:
root@reseller10 [~]# mdadm /dev/md1 -a /dev/sdb3
mdadm: re-added /dev/sdb3
root@SERVER [~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sdb1[1] sda1[0]
521984 blocks [2/2] [UU]
md1 : active raid1 sdb3[1] sda3[0]
483668864 blocks [2/1] [U_]
[>....................] recovery = 0.0% (2432/483668864) finish=6448.8min speed=1216K/sec
Running: echo 100000 > /proc/sys/dev/raid/speed_limit_min will speed up the software raid rebuild process:
root@SERVER [~]# cat /proc/mdstat
Personalities : [raid1]
md0 : active raid1 sdb1[1] sda1[0]
521984 blocks [2/2] [UU]
md1 : active raid1 sdb3[2] sda3[0]
483668864 blocks [2/1] [U_]
[==>..................] recovery = 11.0% (53583104/483668864) finish=1030.4min speed=6954K/sec
unused devices: