Re: Can't add drive to array 3.3 & 3.2.3

[NeilBrown <neilb@suse.de>]

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On Fri, 06 Apr 2012 10:20:57 +0800 Brad Campbell <lists2009@fnarfbargle.com>
wrote:

> G'day Neil,
> 
> I've got a vanilla 3.3 kernel, and mdadm v3.2.3.

Having now seen the real strace:


Yeah, that's a bad combination when bitmaps are involved.
mdadm v.3.2.3 has a bug with adding bitmaps.  It uses O_DIRECT writes from a
non-aligned buffer.

You could use the mdadm from my .git, and it would fix that problem, but then
there is a kernel bug (fixed in 3.3.2 I think) which causes an oops.

Probably safest to go back to mdadm-3.2.2, but going forward  to
linux.3.3.2 and mdadm-.git would work too.

NeilBrown

> 
> I have a 10 drive raid 6 :
> root@srv:~# mdadm --detail /dev/md0
> /dev/md0:
>          Version : 1.2
>    Creation Time : Tue Apr  5 18:14:42 2011
>       Raid Level : raid6
>       Array Size : 15628106752 (14904.12 GiB 16003.18 GB)
>    Used Dev Size : 1953513344 (1863.02 GiB 2000.40 GB)
>     Raid Devices : 10
>    Total Devices : 9
>      Persistence : Superblock is persistent
> 
>    Intent Bitmap : Internal
> 
>      Update Time : Fri Apr  6 10:11:46 2012
>            State : active, degraded
>   Active Devices : 9
> Working Devices : 9
>   Failed Devices : 0
>    Spare Devices : 0
> 
>           Layout : left-symmetric
>       Chunk Size : 128K
> 
>             Name : storage1:0_0
>             UUID : 0f24724f:8e39ff45:4ed83efe:cad4dd84
>           Events : 74069
> 
>      Number   Major   Minor   RaidDevice State
>         0       8       48        0      active sync   /dev/sdd
>         1       0        0        1      removed
>         4       8      144        2      active sync   /dev/sdj
>        11       8       80        3      active sync   /dev/sdf
>        10       8       16        4      active sync   /dev/sdb
>         9       8        0        5      active sync   /dev/sda
>         8       8       32        6      active sync   /dev/sdc
>         7       8       64        7      active sync   /dev/sde
>         6       8       96        8      active sync   /dev/sdg
>         5       8      128        9      active sync   /dev/sdi
> 
> When I go to add a disk to it :
> mdadm --add /dev/md0 /dev/sdh
> 
> mdadm creates a superblock on the disk, but there is nothing in dmesg, nor /proc/mdstat.
> 
> I've attached an strace of the mdadm --add /dev/md0 /dev/sdh for information.
> 
> Not an urgent query, but I thought it odd enough to bring up.
> 
> Regards,
> Brad


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