On Sat, 21 Jul 2012 14:11:03 -0700
walt <email@example.com> wrote:
> I know there are a few lvm2 experts lurking here
> I have a 500gig disk that is split roughly in half between two volume
> groups, each containing four physical volumes, and each vg is
> formatted into an ext4 filesystem of roughly 250GB.
> What I plan to do is merge the two volume groups into one, containing
> one big ext4 filesystem, which will contain all of the files currently
> on the disk.
> Can this be done without copying one of the existing ext4 filesystems
> to a separate drive first, and then copying it back after extending
> the remaining vg/filesystem? (One filesystem has 24GB free and the
> other has 25GB free.)
> I'm expecting a "no" but I'd like to be wrong
For the most part, the answer is no.
But to be totally accurate, it can be done - you just have to shuffle
partitions and contents around on the disk a lot in this fashion:
Move something a bit further towards the end,
Extend the thing in front of it to use the now-free space.
But be warned, it's a complete PITA and a lot like playing the "15
pieces" game with your disk volumes.
You have about 10% free space on both vgs, so the odds you can move
things around successfully are not good. Get yourself a 500G portable
drive to help with the migration.