[Novalug] LVM Snapshots

[American Dave Kline]

On Sun, Dec 19, 2010 at 03:52:39AM -0500, James Ewing Cottrell 3rd wrote:
>   Peter Larsen wrote:
> 
> "Snapshots are fine; just don't mount your root on a snapshot."
> 
> This is precisely the question I asked!
> 
> Dave says "Yes, this is OK". Now who is right?

Peter mentioned things that were important, that
snapshots consume I/O and you'll have to worry about running out of
space in a snapshot -- very important things to worry about with a root
filesystem.  Hence my suggestion of --merge, which means if you like
your snapshot you can merge it to its origin.

Peter also gave a great LVM talk.

> And BTW, there is No Such Thing as "lvconvert --merge". At least not in 
> CentOS 5.5.

Correct.  RHEL 6, Fedora 14, etc, contain --merge.  CentOS is based off
of RHEL 5 at present.  Red Hat is offering more affordable ways to get
RHEL 6, you might want to have a look.

Consider purchasing RHEL as an investment in CentOS's upstream.

That said, I suppose you could try booting a live distro and merging
the snapshot(s) using the live LVM.  I've never done this, but would
investigate if it was important.

Regards,
-A. Dave