On 08/28/2015 04:22 AM, David C. Rankin wrote:
All,
I had a disc-controller failure on a server running several raid1 arrays. The
disks are fine, but I have had the root partition come up in degraded mode. What
is the best way to tell mdraid to resync the disks? Here are the symptoms:
# cat /proc/mdstat
Personalities : [raid1]
md1 : active raid1 sdb7[1]
52396032 blocks super 1.2 [2/1] [_U]
md3 : active raid1 sdb6[1] sda6[0]
1047552 blocks super 1.2 [2/2] [UU]
md2 : active raid1 sda8[0] sdb8[1]
922944192 blocks super 1.2 [2/2] [UU]
bitmap: 0/7 pages [0KB], 65536KB chunk
md0 : active raid1 sda5[0] sdb5[1]
204608 blocks super 1.2 [2/2] [UU]
unused devices: <none>
# mdadm --misc --detail /dev/md1
/dev/md1:
Version : 1.2
Creation Time : Wed Nov 27 04:35:49 2013
Raid Level : raid1
Array Size : 52396032 (49.97 GiB 53.65 GB)
Used Dev Size : 52396032 (49.97 GiB 53.65 GB)
Raid Devices : 2
Total Devices : 1
Persistence : Superblock is persistent
Update Time : Fri Aug 28 04:12:18 2015
State : clean, degraded
Active Devices : 1
Working Devices : 1
Failed Devices : 0
Spare Devices : 0
Name : archiso:1
UUID : 320d86f7:22999af5:5eeefee1:35cd8970
Events : 100308
Number Major Minor RaidDevice State
0 0 0 0 removed
1 8 23 1 active sync /dev/sdb7
Reading, it looks like one approach is the boot the install media and then zero
the superblock on /dev/sda7 and then reboot. Will that force a rebuild, or do I
need to fail and remove the disk first? I was thinking:
# mdadm --zero-superblock /dev/sda7
should set it up for a rebuild without more. Is this a sane approach?
This adds a bit more of the picture. It's like sda7 doesn't even know it was
kicked out. There are no disk errors logged for either of the drives:
# mdadm -E /dev/sd[ab]7
/dev/sda7:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x8
Array UUID : 320d86f7:22999af5:5eeefee1:35cd8970
Name : archiso:1
Creation Time : Wed Nov 27 04:35:49 2013
Raid Level : raid1
Raid Devices : 2
Avail Dev Size : 104792064 (49.97 GiB 53.65 GB)
Array Size : 52396032 (49.97 GiB 53.65 GB)
Data Offset : 65536 sectors
Super Offset : 8 sectors
Unused Space : before=65448 sectors, after=0 sectors
State : active
Device UUID : f5a48ea1:bce2f6f0:f47f9c0b:bad1d64d
Update Time : Sat Aug 8 17:17:21 2015
Bad Block Log : 512 entries available at offset 72 sectors - bad blocks present.
Checksum : 2c45bcef - correct
Events : 280
Device Role : Active device 0
Array State : AA ('A' == active, '.' == missing, 'R' == replacing)
/dev/sdb7:
Magic : a92b4efc
Version : 1.2
Feature Map : 0x8
Array UUID : 320d86f7:22999af5:5eeefee1:35cd8970
Name : archiso:1
Creation Time : Wed Nov 27 04:35:49 2013
Raid Level : raid1
Raid Devices : 2
Avail Dev Size : 104792064 (49.97 GiB 53.65 GB)
Array Size : 52396032 (49.97 GiB 53.65 GB)
Data Offset : 65536 sectors
Super Offset : 8 sectors
Unused Space : before=65448 sectors, after=0 sectors
State : clean
Device UUID : 66e069cc:02daa93e:1d4a6eea:e5c21cb7
Update Time : Fri Aug 28 04:35:31 2015
Bad Block Log : 512 entries available at offset 72 sectors - bad blocks present.
Checksum : ed07de3b - correct
Events : 100584
Device Role : Active device 1
Array State : .A ('A' == active, '.' == missing, 'R' == replacing)
Do I try a --re-add on sda7 or just zero it for a complete rebuild? Any help
appreciated.
--
David C. Rankin, J.D.,P.E.
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