[nzlug] LVM and toast....

[Nevyn]

This won't work because it's a raid 5 device.

This means it's got tolerance for one device to fail but not two. So
once 2 devices fail, the raid can't became active as half the data is
missing.

On 4/2/07, Andrew Bruce <abruce at hope-st.ath.cx> wrote:
> 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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> >>
> >
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