Hello -
I'm not finding any documentation on forcing disks back online after
they are marked as failed, and could use some help on this.
Specifically, I have a 14 disk software raid5 array, which suffered
2 disks failing (the second failed during the resync). Because the
first disk was failed for several hours of disk activity, it obviously
doesn't have up-to-date information on it, and it is currently marked
as removed. The second disk seems to have only an 8K area of the disk
(in the middle) that cannot be read. I have dd'd the disk to a spare,
and would like to put the disk online in place of the 2nd disk.
However, I don't see any way to 'force a disk online' like you can on
hardware raid. How can I change the status? If I can force the disk
online, I should be able to mount the array in degraded mode, and
recover most everything, except for the data that lies on the stripe
using those 8K.
Any help would be appreciated.
- Nathan
CSUA, UC Berkeley
Below is the output I have from looking at the status of each drive.
The very last disk is the partially rebuilt replacement for Raid
Device 7. I need to mark RaidDevice 8 as active.
screwdriver:~# mdadm --examine /dev/scsi/host4/bus0/target1/lun0/part1
/dev/scsi/host4/bus0/target1/lun0/part1:
Magic : a92b4efc
Version : 00.90.00
UUID : 783f1b1d:be8dfcb6:9ff5a8df:54164efd
Creation Time : Thu Jul 24 02:43:26 2003
Raid Level : raid5
Device Size : 35005504 (33.38 GiB 35.85 GB)
Raid Devices : 14
Total Devices : 15
Preferred Minor : 0
Update Time : Thu Jan 8 20:37:35 2004
State : dirty, no-errors
Active Devices : 12
Working Devices : 13
Failed Devices : 2
Spare Devices : 1
Checksum : 553968b6 - correct
Events : 0.16
Layout : left-symmetric
Chunk Size : 64K
Number Major Minor RaidDevice State
this 1 65 1 1 active sync /dev/scsi/host4/bus0/target1/lun0/part1
0 0 8 241 0 active sync /dev/scsi/host4/bus0/target0/lun0/part1
1 1 65 1 1 active sync /dev/scsi/host4/bus0/target1/lun0/part1
2 2 65 17 2 active sync /dev/scsi/host4/bus0/target2/lun0/part1
3 3 65 33 3 active sync /dev/scsi/host4/bus0/target3/lun0/part1
4 4 65 49 4 active sync /dev/scsi/host4/bus0/target4/lun0/part1
5 5 65 65 5 active sync /dev/scsi/host4/bus0/target5/lun0/part1
6 6 65 81 6 active sync /dev/scsi/host4/bus0/target6/lun0/part1
7 7 0 0 7 faulty removed
8 8 65 113 8 faulty /dev/scsi/host4/bus0/target8/lun0/part1
9 9 65 129 9 active sync /dev/scsi/host4/bus0/target9/lun0/part1
10 10 65 145 10 active sync /dev/scsi/host4/bus0/target10/lun0/part1
11 11 65 161 11 active sync /dev/scsi/host4/bus0/target11/lun0/part1
12 12 65 177 12 active sync /dev/scsi/host4/bus0/target12/lun0/part1
13 13 65 193 13 active sync /dev/scsi/host4/bus0/target13/lun0/part1
14 14 65 97 14 /dev/scsi/host4/bus0/target7/lun0/part1
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