Backup of docker would either be full host - for a simple and inflexible setup, or you do data and config backup (volumes mounted in docker), and rely on docker rebuilding the images.

This last type is more overhead in configuration of backup, but you can restore your containers on any host, individually

There are big differences between these two technologies. LXC is closer to a virtual machine than a docker setup. You could mimic most of a dockerfile if you wanted, but it’s not a replacement.

Most of us will use a mix og docker-hosts(vm’s running docker) and lxc. Reasons for this is that some stuff is easier to maintain in docker as it’s the preferred release channel.

You can also move vm’s to other datacenter hosts if needed - and with shared storage this is quick and mean no downtime. Lxc are stuck on the host.

Honestly, what you’re trying to do is a great use case for docker already. I suggest learning more about how to use docker, take backups, restore from backups, etc. E.g., I have a NFSv4 share that I store all of my containerized services’ config and data files in. Any time I need to restore a precious version, it’s as easy as restoring the previous version files and starting the previous version container.