My backup server has been running ZFS for over a decade and I love it for that and for archives. The bulk of my systems run ext4, because until 20.04 it wasn't

My backup server has been running ZFS for over a decade and I love it for that and for archives. The bulk of my systems run ext4, because until 20.04 it wasn't really a thing to have bootable ZFS on Ubuntu (yes you could do it, I didn't because reasons). My backups use rsync to pick up incremental changes, so full filesystem scans are involved and the backup server gets pretty busy because of those. One interesting thing I did at one point was to clone and mount LVs of running Windows VMs, so I could then rsync backup them on the same backup server. With the exception of a handful of physical boxes, my fleet is entirely Linux VMs running on Ganeti hosts with LVM for storage. This project has me imagining doing VM-level backups by talking to the ganeti hosts and backing up LVM clones outside the host, rather than rsyncing into the host.