[linux-lvm] exposing snapshot block device

[Zdenek Kabelac]

Dne 07. 09. 20 v 16:14 Dalebjörk, Tomas napsal(a):
> Hi Mikulas,
> 
> Thanks for the replies
> 
> I am confused now with the last message?
> 
> LVM doesn't support taking existing cow device and attaching it to an existing 
> volume?
> 
> Isn't that what "lvconvert --splitsnapshot" & "lvconvert -s" is ment to be doing?
> 
> lets say that I create the snapshot on a different device using these steps:
> 
> root at src# lvcreate -s -L 10GB -n lvsnap vg/lv /dev/sdh
> root at src# lvconvert ---splitsnapshot vg/lvsnap
> root at src# echo "I now move /dev/sdb to another server"
> root at tgt# lvconvert -s newvg/newlv vg/lvsnap
> 

Hi

This is only supported as long as you stay within VG.
So newlv & lvsnap must be in a single VG.

Note - you can 'vgreduce' PV from VG1 and vgextend to VG2.
But it always work on whole PV base - you can't mix
LV between VGs.

Zdenek