“Also, if you use LVM across hard drives, you may lose all your data when only one drive fails.”
(Source: server - What is LVM and what is it used for? - Ask Ubuntu, - last third).
Just a question first: Why don’t you using zfs ?
I assume you have to use LVM, right?
Which OS are you using ?
Which version of LXD ?
Do you know there is a snap LXD - THE current version - out there as well?
Before we can dive into deeper have you seen this: Backing up containers - #6 by sqllyw and this Backup the container and install it on another server - #15 by tws?
What about Ubuntu 18.04 Root on ZFS · openzfs/zfs Wiki · GitHub or
Ubuntu 16.04 Root on ZFS · openzfs/zfs Wiki · GitHub