[mythtv-users] mdadm help, please

[John Drescher]

On Sat, Apr 25, 2009 at 1:06 AM, Joel Means <means.joel at gmail.com> wrote:
> On Fri, Apr 24, 2009 at 8:24 AM, Joel Means <means.joel at gmail.com> wrote:
>>
>> Thanks, John.  I have subscribed and will send my original message to the
>> linux-raid mailing list.  I am willing to try any suggestions you may have
>> as well.
>>
>> Joel
>>
>
> Just an update.  I found through a lot of googling that the problem
> was that I did not have large block device support compiled into my
> kernel (CONFIG_LBD).  I set that to yes, recompiled, and now the raid
> shows up correctly.  Unfortunately, it looks like my fiddling with the
> array did hose my filesystem.  The array is currently rebuilding, but
> at the moment, running  an fsck gives me this:
>
> # jfs_fsck -d -nv /dev/md0
> jfs_fsck version 1.1.12, 24-Aug-2007
> processing started: 4/24/2009 23.2.28
> The current device is:  /dev/md0 [xchkdsk.c:1527]
> Open(...READONLY...) returned rc = 0 [fsckpfs.c:3199]
> Invalid magic number in the superblock (P). [fsckmeta.c:1944]
> Invalid magic number in the superblock (S). [fsckmeta.c:1944]
>
> The superblock does not describe a correct jfs file system.
>
> If device /dev/md0 is valid and contains a jfs file system,
> then both the primary and secondary superblocks are corrupt
> and cannot be repaired, and fsck cannot continue.
>
> Otherwise, make sure the entered device /dev/md0 is correct.
>
> Once it finishes rebuilding (sometime tomorrow, hopefully), I will try
> to work on that.  I am open to any suggestions of what can be done.  I
> have read about trying to copy the superblock from a good filesystem
> of the same size, but I don't know if I can achieve that without an
> empty 3TB of space.  I will have to play with my other raid, but it
> has data on it, so I want to be careful.
>
Its possible that the resync that terminated did this. I do not know
the details of how CONFIG_LBD operates though. Mainly because I use
only 64 bit kernels on my 64 bit x86_64 capable machines (well since
2004) so there are only a few software raid machines left that are 32
bit.

John