[CentOS] offline root lvm resize

Sat Jul 30 11:40:33 UTC 2011
Alexander Dalloz <ad+lists at uni-x.org>

Am 30.07.2011 10:37, schrieb Sean Hart:
> So here goes...
> First some back story
>      -Centos 5 with latest updates as of yesterday. kernel is
> 2.6.18-238.19.1.el5
>      -setup is raid 1 for /boot and lvm over raid6 for everything else
> 
>      -  The / partition (lvm "RootVol") had run out of room... (100%
> full, things where falling appart...)
> 
> I resized the root volume (from 20GiB to 50GiB). This was done from a
> fedora 15 livecd, seemed like a better idea than doing it on a live
> system at the time.... After the resize the content of all the lvs
> could be mounted and all data was still there (all this from within
> fedora).

You would better have used the CentOS 5 install media to run into rescue
mode and then to chroot into the system, given you felt better to do an
offline resizing. Though online resizing (increasing an LV) is trouble
free from my experience. Well, if / is completely full the offline route
may indeed be better.

> The problem is when i try to reboot into centos as the root volume
> cannot be found.
> 
> boot message goes as follows
> 
> ...
> No Volume groups found
> Volume Group "RaidVolGrp" not found
> ...
> Kernel panic
> 
> 
> the UUID's have not changed, but there is definitely a missing link,
> probably something dumb...
> 
> I would greatly appreciate if anyone could help point me in the right
> direction..
> 
> a bit more info
> 
> # lvscan
>   ACTIVE            '/dev/RaidVolGrp/RootVol' [50.00 GiB] inherit
>   ACTIVE            '/dev/RaidVolGrp/HomeVol' [250.00 GiB] inherit
>   ACTIVE            '/dev/RaidVolGrp/SwapVol' [2.44 GiB] inherit
>   ACTIVE            '/dev/RaidVolGrp/MusicVol' [350.00 GiB] inherit
>   ACTIVE            '/dev/RaidVolGrp/VideoVol' [350.00 GiB] inherit
>   ACTIVE            '/dev/RaidVolGrp/PicturesVol' [300.00 GiB] inherit
>   ACTIVE            '/dev/RaidVolGrp/MiscVol' [60.00 GiB] inherit
>   ACTIVE            '/dev/RaidVolGrp/ShareddocVol' [60.00 GiB] inherit
>   ACTIVE            '/dev/RaidVolGrp/VMVol' [60.00 GiB] inherit
>   ACTIVE            '/dev/RaidVolGrp/TorrentVol' [50.00 GiB] inherit

That is output from running the Fedora LiveCD?

Boot up with the CentOS 5 DVD into rescue mode, let it detect the
existing LVMs. Go into /etc/lvm/backup and validate the info that's
saved there and to check what CentOS sees.

> sh

Alexander