On Monday, January 14, 2013 3:11 PM Dorau, Lukasz [off-list ref] wrote:

On Monday, January 14, 2013 1:56 AM chris [off-list ref] wrote:

quoted

[292295.923942] bio: create slab <bio-1> at 1
[292295.923965] md/raid:md126: not clean -- starting background
reconstruction
[292295.924000] md/raid:md126: device sdb operational as raid disk 2
[292295.924005] md/raid:md126: device sdc operational as raid disk 1
[292295.924009] md/raid:md126: device sde operational as raid disk 0
[292295.925149] md/raid:md126: allocated 4250kB
[292295.927268] md/raid:md126: cannot start dirty degraded array.

Hi

*Remember to backup the disks you have before trying the following! *

You can try starting dirty degraded array using:
#  mdadm --assemble --force ....

I meant adding --force option to:
# mdadm --create --verbose --force /dev/md/Volume0 /dev/sdc missing /dev/sdb /dev/sdd --raid-devices 4 --level=5

Be very careful using "--force" option, because it can cause data corruption!

Lukasz

See also the "Boot time assembly of degraded/dirty arrays" chapter in:
http://www.kernel.org/doc/Documentation/md.txt
(you can boot with option md-mod.start_dirty_degraded=1)

Lukasz

quoted

[292295.929666] RAID conf printout:
[292295.929677]  --- level:5 rd:4 wd:3
[292295.929683]  disk 0, o:1, dev:sde
[292295.929688]  disk 1, o:1, dev:sdc
[292295.929693]  disk 2, o:1, dev:sdb
[292295.930898] md/raid:md126: failed to run raid set.
[292295.930902] md: pers->run() failed ...
[292295.931079] md: md126 stopped.
[292295.931096] md: unbind<sdb>
[292295.944228] md: export_rdev(sdb)
[292295.944267] md: unbind<sdc>
[292295.958126] md: export_rdev(sdc)
[292295.958167] md: unbind<sde>
[292295.970902] md: export_rdev(sde)
[292296.219837] device-mapper: table: 252:1: raid45: unknown target type
[292296.219845] device-mapper: ioctl: error adding target to table
[292296.291542] device-mapper: table: 252:1: raid45: unknown target type
[292296.291548] device-mapper: ioctl: error adding target to table
[292296.310926] quiet_error: 1116 callbacks suppressed
[292296.310934] Buffer I/O error on device dm-0, logical block 3907022720
[292296.310940] Buffer I/O error on device dm-0, logical block 3907022721
[292296.310944] Buffer I/O error on device dm-0, logical block 3907022722
[292296.310949] Buffer I/O error on device dm-0, logical block 3907022723
[292296.310953] Buffer I/O error on device dm-0, logical block 3907022724
[292296.310958] Buffer I/O error on device dm-0, logical block 3907022725
[292296.310962] Buffer I/O error on device dm-0, logical block 3907022726
[292296.310966] Buffer I/O error on device dm-0, logical block 3907022727
[292296.310973] Buffer I/O error on device dm-0, logical block 3907022720
[292296.310977] Buffer I/O error on device dm-0, logical block 3907022721
[292296.319968] device-mapper: table: 252:1: raid45: unknown target type
[292296.319975] device-mapper: ioctl: error adding target to table

Any ideas from here? Am I up the creek without a paddle? :(

thanks to everyone for all your help so far
chris

On Sun, Jan 13, 2013 at 4:05 PM, Dan Williams [off-list ref] wrote:

quoted

On 1/13/13 11:00 AM, "chris" [off-list ref] wrote:

quoted

Neil/Dave,

Is it not possible to create imsm container with missing disk?
If not, Is there any way to recreate the array with all disks but
prevent any kind of sync which may overwrite array data?

The example was in that link I sent:

mdadm --create /dev/md/imsm /dev/sd[bde] -e imsm
mdadm --create /dev/md/vol0 /dev/sde missing /dev/sdb /dev/sdd -n 4 -l 5

The first command marks all devices as spares.  The second creates the
degraded array.

You probably want at least sdb and sdd in there since they have a copy of
the metadata.

--
Dan

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