How to re-add RAID-10 dropped drive?
- by thiesdiggity
I have a problem that I can't seem to solve. We have a Ubuntu server setup with RAID-10 and two of the drives dropped out of the array. When I try to re-add them using the following command:
mdadm --manage --re-add /dev/md2 /dev/sdc1
I get the following error message:
mdadm: Cannot open /dev/sdc1: Device or resource busy
When I do a "cat /proc/mdstat" I get the following:
Personalities : [linear] [multipath] [raid0] [raid1] [raid6] [raid5] [raid4] [r$
md2 : active raid10 sdb1[0] sdd1[3]
1953519872 blocks 64K chunks 2 near-copies [4/2] [U__U]
md1 : active raid1 sda2[0] sdc2[1]
468853696 blocks [2/2] [UU]
md0 : active raid1 sda1[0] sdc1[1]
19530688 blocks [2/2] [UU]
unused devices: <none>
When I run "/sbin/mdadm --detail /dev/md2" I get the following:
/dev/md2:
Version : 00.90
Creation Time : Mon Sep 5 23:41:13 2011
Raid Level : raid10
Array Size : 1953519872 (1863.02 GiB 2000.40 GB)
Used Dev Size : 976759936 (931.51 GiB 1000.20 GB)
Raid Devices : 4
Total Devices : 2
Preferred Minor : 2
Persistence : Superblock is persistent
Update Time : Thu Oct 25 09:25:08 2012
State : active, degraded
Active Devices : 2
Working Devices : 2
Failed Devices : 0
Spare Devices : 0
Layout : near=2, far=1
Chunk Size : 64K
UUID : c6d87d27:aeefcb2e:d4453e2e:0b7266cb
Events : 0.6688691
Number Major Minor RaidDevice State
0 8 17 0 active sync /dev/sdb1
1 0 0 1 removed
2 0 0 2 removed
3 8 49 3 active sync /dev/sdd1
Output of df -h is:
Filesystem Size Used Avail Use% Mounted on
/dev/md1 441G 2.0G 416G 1% /
none 32G 236K 32G 1% /dev
tmpfs 32G 0 32G 0% /dev/shm
none 32G 112K 32G 1% /var/run
none 32G 0 32G 0% /var/lock
none 32G 0 32G 0% /lib/init/rw
tmpfs 64G 215M 63G 1% /mnt/vmware
none 441G 2.0G 416G 1% /var/lib/ureadahead/debugfs
/dev/mapper/RAID10VG-RAID10LV
1.8T 139G 1.6T 8% /mnt/RAID10
When I do a "fdisk -l" I can see all the drives needed for the RAID-10.
The RAID-10 is part of the /dev/mapper, could that be the reason why the device is coming back as busy? Anyone have any suggestions on what I can try to get the drives back into the array?
Any help would be greatly appreciated.
Thanks!
