[nzlug] LVM and toast....

[Andrew Bruce]

Sorry, I should have mentioned that you may need to remove them from 
being spares first, before re-adding them.

This should force a rebuild onto the 'spare' disk:

mdadm --remove /dev/<raid_device> /dev/<drive_and_partition>

should do the trick, then the command below.

Andrew


Andrew Bruce wrote:
> If they are marked as spares what about trying:
>
> mdadm --add /dev/<raid_device> /dev/<drive_and_partition>
>
> eg.
>
> mdadm --add /dev/md0 /dev/hdc1
>
> Andrew
>
>
> Nevyn wrote:
>> Nevermind - turns out that the raid device isn't starting as I'd hope.
>> It's showing 2 disks as spares. There was a command suggested in a few
>> places but they haven't helped at all.
>> mdadm --assemble --force
>>
>> The only other reference I found to try and fix this error said the 
>> following:
>> Rewrite the RAID superblocks by mkraid --force
>>
>> Unfortunately raidtools is no longer in Ubuntu.
>>
>> On 4/1/07, Nevyn <nevynh at gmail.com> wrote:
>>> Well.... took the dive. Ran the command - (read the page properly
>>> which sorted the question I asked just a few minutes ago). This is the
>>> output I got....
>>>
>>>   Incorrect metadata area header checksum
>>>   Incorrect metadata area header checksum
>>>   Incorrect metadata area header checksum
>>>   Couldn't find device with uuid 
>>> '92rPwd-7BkZ-x0uf-N9Lb-yTJa-tXjD-ckcHCr'.
>>>   Device volume1 not found (or ignored by filtering).
>>>
>>> Umm... help?!?
>>>
>>> On 4/1/07, Nevyn <nevynh at gmail.com> wrote:
>>> > Just another quick question....
>>> >
>>> > pvcreate --uuid "<some_long_string>" --restorefile
>>> > /etc/lvm/archive/VolumeGroupName_XXXXX.vg <PhysicalVolume>
>>> >
>>> > What should <some_long_string> be set to or does it not matter?
>>> >
>>> > On 4/1/07, Jasper Bryant-Greene <jasper at albumltd.co.nz> wrote:
>>> > > The file in /etc/lvm/backup is what you want. It's a textual 
>>> dump of
>>> > > your volume group's configuration.
>>> > >
>>> > > Cheers,
>>> > > Jasper
>>> > >
>>> > >
>>> > > On Sun, 2007-04-01 at 16:58 +1200, Nevyn wrote:
>>> > > > Hi,
>>> > > >
>>> > > > Things are going very badly at the moment - suddenly the 
>>> output of
>>> > > > /proc/mdstat was showing that 2 disks had suddenly dropped off 
>>> - 1 was
>>> > > > showing a failure and I have no idea why the other one wasn't 
>>> in there
>>> > > > except that it was showing (s) next to it.
>>> > > >
>>> > > > Of course this meant that suddenly the array wasn't working which
>>> > > > explains all the wierd behaviour I had suddenly started 
>>> experiencing.
>>> > > > After a few failed attempts to get the array to rebuild itself, I
>>> > > > reboot the machine and lo and behold, the raid seems to have 
>>> gotten
>>> > > > itself together.
>>> > > >
>>> > > > Still wasn't mounting though so I ran vgscan - and got the 
>>> following message:
>>> > > >   Reading all physical volumes.  This may take a while...
>>> > > >   Incorrect metadata area header checksum
>>> > > >
>>> > > > The lvm howto has this to say about it:
>>> > > > "If you get the warning "incorrect metadata area header 
>>> checksum" or
>>> > > > something about not being able to find PV with UUID foo, you 
>>> probably
>>> > > > toasted the volume group descriptor area and lvm startup can't 
>>> occur."
>>> > > >
>>> > > > and then has a command to restore the stuffed bits:
>>> > > > pvcreate --uuid "<some_long_string>" --restorefile
>>> > > > /etc/lvm/archive/VolumeGroupName_XXXXX.vg <PhysicalVolume>
>>> > > >
>>> > > > However, I don't have a .vg file anywhere that I can find. 
>>> There is a
>>> > > > file in the back up directory but I'm a little unsure about 
>>> this as it
>>> > > > doesn't have a .vg extension.
>>> > > >
>>> > > > Does anyone know how I can fix all this?
>>> > > >
>>> > > > Regards,
>>> > > > Nevyn.
>>> > > >
>>> > > > _______________________________________________
>>> > > > NZLUG mailing list NZLUG at linux.net.nz
>>> > > > http://www.linux.net.nz/cgi-bin/mailman/listinfo/nzlug
>>> > > --
>>> > > Jasper Bryant-Greene <jasper at albumltd.co.nz>
>>> > > Album Limited
>>> > >
>>> > > _______________________________________________
>>> > > NZLUG mailing list NZLUG at linux.net.nz
>>> > > http://www.linux.net.nz/cgi-bin/mailman/listinfo/nzlug
>>> > >
>>> > >
>>> > >
>>> >
>>>
>>
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