@BlueChip
Like others, I disagree with @jklass. I think btrfs is sufficiently stable, and the benefit of snapshots is a big plus of btrfs.
This is bad advice. It may well break your LXC installation. Instead, see the following thread for advice on how to move LXCs from one FS to another…:
Read the entire thread.
I am sorry, but I cannot comment on 3.10s new feature to move /srv to external storage, as I have never used it.