I installed Proxmox Backup Server in a VM on my nas to see what all the fuss was about. I messed with it for a but but then the install got botched (not PBS’s fault) and I didn’t bother messing with it anymore. What I have been doing is, on each of my nodes, just setting up scheduled backups of VMs to a share on my NAS. I can’t figure out why using PBS would be any better that just doing that but people seem to like it. I only have to do this once on each node. Could anyone enlighten me as to what I am not seeing in PBS that makes it better?
Other people have mentioned de-duplication; to better explain it, PBS backups can be incremental - they will only save the changes between the current state and the previous backup. This will save you a TON of space on backups, which means you can take them more often and retain them for longer.
PVE’s backup just makes a compressed copy of the disk images and calls it a day.
PBS runs as a separate solution because that way it can be used to manage multiple clusters, it can keep backups isolated from those clusters, etc.
I’ve found it easier to just keep storage snapshots of the backing NAS for the VM images. Back those up on another slow NAS. And periodically refresh an off-site storage.
It’s not as atomic, but I can restore the VM images to various points in time.