Bug#237754: lvm2: snapshot doesn't work

[adrian]

Just another person hitting this, although I'll just say the issues
I've hit:

lvcreate -s -n snaplv -L 50M /dev/rootvg/rootlv 

This pops up a usage error (odd since it's more or less a cut and
paste of example usage).  Then I read this bug report and loaded
dm_snapshot.  Looks like I had the usage fine - I'd be much better if we
had a "kernel doesn't support snapshots (load dm_snapshot module?)
error.

The box then partially hung (I could type but couldn't login at all).

On a reboot "can't expand LV: snapshot support missing from kernel?"
and rootvg wouldn't mount (which has my rootlv "/" on it so I couldn't
boot).  Hmmm - bug #288354 says you can't snapshot "/" (status as of Jan 05).

Fortunately if I use a different LV at least it doesn't lock out the
whole VG on a reboot :-)

Adrian