I have a production raid array that has hit problems. Luckily when I configured it I assigned a hot spare. Here is what the status looks like now:
mdadm --detail /dev/md2
/dev/md2:
Version : 0.90
Creation Time : Sun Jul 4 14:49:33 2010
Raid Level : raid5
Array Size : 3907039744 (3726.04 GiB 4000.81 GB)
Used Dev Size : 976759936 (931.51 GiB 1000.20 GB)
Raid Devices : 5
Total Devices : 6
Preferred Minor : 2
Persistence : Superblock is persistent
Update Time : Sun Aug 5 11:56:50 2012
State : active, degraded, recovering
Active Devices : 4
Working Devices : 5
Failed Devices : 1
Spare Devices : 1
Layout : left-symmetric
Chunk Size : 64K
Rebuild Status : 63% complete
UUID : dce41d37:804dea59:e5727503:733c194b
Events : 0.13139
Number Major Minor RaidDevice State
0 8 145 0 active sync /dev/sdj1
1 8 161 1 active sync /dev/sdk1
2 8 177 2 active sync /dev/sdl1
3 8 193 3 active sync /dev/sdm1
5 8 225 4 spare rebuilding /dev/sdo1
6 8 209 - faulty spare /dev/sdn1
If and when this completes however what do I need to do to replace the faulty drive as a new spare? Ideally I don't want to have to take the system down next week.