[dm-devel] Possible bug in mirror target

[Bryn M. Reeves]

On Wed, Feb 13, 2019 at 03:21:52PM +0100, Zdenek Kabelac wrote:
> If you have this free space it's surely not a bad thing - but there
> are many cases, you can get any free space - majority of filesystems
> does not support shrinking - so the only 'free' space you can
> get is by adding new storage to VG - again quite limiting factor.

Probably obvious to many, but if you find yourself in this situation
using the Red Hat / Fedora default layout created by Anaconda, the
easiest solution is normally to "steal" one extent from the auto-
configured swap LV, and donate it to the mirror conversion:

  # swapoff -a
  # lvresize -l -1 rhel/swap
  # mkswap /dev/rhel/swap
  # swapon -a
  # lvchange -m1 ...

This will always work with the automatic layouts provided by those
distros.

Regards,
Bryn.