In trying to reshape a raid5 array, I encountered some problems.
I was trying to reshape from raid5 3->4 devices. The reshape process
started with seeming no problems, however i noticed in the kernel log
a number of ata3.00: failed command: WRITE FPDMA QUEUED errors.
In trying to determine if this was going to be bad for me, I disabled
ncq on this device. Looking at the log, i notice around the same time
/dev/sdd reported problems and took itself offline.
At this point the reshape seemed to be continuing w/o issue, even
though one of the drives was offline.. I wasn't sure that this made
sense.
Shortly after, I noticed that the progress on the reshape had stalled.
I tried changing the stripe_cache_size from 256 to [1024|2048|4096],
but the reshape did not resume. top reported that the reshape process
was using 100% of one core, and the load average was climbing into the
50's
At this point I rebooted. The array does not start.
Can the reshape be restarted? I cannot figure out where the backup
file ended up. It does not seem to be where I thought I saved it.
Can I assemble this array with only the 3 original devices? Is there a
way to recover at least some of the data on the array? I have various
backups, but there are some stuff that was not "critical' but would
still be handy to not loose.
Various logs that could be helpful: md_d2 is the array in question.
Thanks..
--Glen
# mdadm --version
mdadm - v3.1.4 - 31st August 2010
# uname -a
Linux palidor 2.6.36-gentoo-r5 #1 SMP Wed Mar 2 20:54:16 EST 2011
x86_64 Intel(R) Core(TM)2 Quad CPU Q9450 @ 2.66GHz GenuineIntel
GNU/Linux
current state:
# cat /proc/mdstat
Personalities : [raid6] [raid5] [raid4] [multipath] [raid1]
md8 : active raid5 sdh1[0] sdg1[4] sdf1[1] sdi1[3] sde1[2]
5860542464 blocks level 5, 512k chunk, algorithm 2 [5/5] [UUUUU]
md_d2 : inactive sdb5[1](S) sda5[0](S) sdd5[2](S) sdc5[3](S)
2799357952 blocks super 0.91
md1 : active raid5 sdd3[2] sdb3[1] sda3[0]
62926336 blocks level 5, 256k chunk, algorithm 2 [3/3] [UUU]
md0 : active raid1 sdb1[1] sda1[0] sdd1[2]
208704 blocks [3/3] [UUU]
# mdadm -E /dev/sdb5 ([abc]) are all similiar.
/dev/sdb5:
Magic : a92b4efc
Version : 0.91.00
UUID : 2803efc9:c5d2ec1e:9894605d:35c5ea6f
Creation Time : Sat Oct 3 11:01:02 2009
Raid Level : raid5
Used Dev Size : 699839488 (667.42 GiB 716.64 GB)
Array Size : 2099518464 (2002.26 GiB 2149.91 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 2
Reshape pos'n : 62731776 (59.83 GiB 64.24 GB)
Delta Devices : 1 (3->4)
Update Time : Sun May 15 11:25:21 2011
State : active
Active Devices : 3
Working Devices : 3
Failed Devices : 1
Spare Devices : 0
Checksum : 2f2eac3a - correct
Events : 114069
Layout : left-symmetric
Chunk Size : 256K
Number Major Minor RaidDevice State
this 1 8 21 1 active sync /dev/sdb5
0 0 8 5 0 active sync /dev/sda5
1 1 8 21 1 active sync /dev/sdb5
2 2 0 0 2 faulty removed
3 3 8 37 3 active sync /dev/sdc5
# mdadm -E /dev/sdd5
/dev/sdd5:
Magic : a92b4efc
Version : 0.91.00
UUID : 2803efc9:c5d2ec1e:9894605d:35c5ea6f
Creation Time : Sat Oct 3 11:01:02 2009
Raid Level : raid5
Used Dev Size : 699839488 (667.42 GiB 716.64 GB)
Array Size : 2099518464 (2002.26 GiB 2149.91 GB)
Raid Devices : 4
Total Devices : 4
Preferred Minor : 2
Reshape pos'n : 18048768 (17.21 GiB 18.48 GB)
Delta Devices : 1 (3->4)
Update Time : Sun May 15 10:51:41 2011
State : clean
Active Devices : 4
Working Devices : 4
Failed Devices : 0
Spare Devices : 0
Checksum : 29dcc275 - correct
Events : 113870
Layout : left-symmetric
Chunk Size : 256K
Number Major Minor RaidDevice State
this 2 8 53 2 active sync /dev/sdd5
0 0 8 5 0 active sync /dev/sda5
1 1 8 21 1 active sync /dev/sdb5
2 2 8 53 2 active sync /dev/sdd5
3 3 8 37 3 active sync /dev/sdc5
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