The real benefit of PBS is it does not store the backup as just a 1:1 dump of the VM disk, it's incremental - if the VM you're backing up for say the 3rd or 4th or 20th time doesn't have much new or changed data, it's not a linearly increasing amount of storage on your backup server, the new backup is actually trivially small. This really helps you have longer backup retention if files aren't actually changing all that often.

I got tired of stressing about whether my backup host might be down when my primary Proxmox host dies, even if they're in different data centers - well, as far as I know anyway! Now I just use BackBlaze B2 storage for the PBS off-site backup (compatible with Amazon S3), albeit it's a little finnicky to set up and working 100%. Yes it's still 'just someone else's computer', but for the ~12 bucks it's costing me for almost 2TB of backup data I am not stressing about it.

You don't technically need to back up the PBS server as there's not much there other than a basic config. As far as the backup data itself, you can mirror to another PBS server or I think it supports S3 for offsite storage.

I have aPBS server and my friend in a different geographic region has one. I backup to mine and he backs up to his. Mine syncs my backups to a data so l store in his, and his summer backups to a data store in mine. These are our offsite backups.

To be clear, we're syncing our proxmox VM backups. But Proxmox Backup Server also has a client app, so I also back up my workstation to my PBS and it also syncs to the remote PBS.

Most people don't. in the event of a total failure you reinstall Proxmox, you configure your networks, then you restore your backups into it.

Honestly it's the same method I've used countless times on VMware / Rubrik.

PBS has a host backup client you can install on non-VMs. You can then configure it to just backup it's operating system files. This works for other Linux machines in the network including the Proxmox server, PBS itself or desktops. I even use it on my LibreELEC raspberry pi tv box.

https://pbs.proxmox.com/docs/backup-client.html

Why would you?

The important part is your VMs and LXCs. Your Proxmox server, at most, requires configuration for specific needs (GPU passthrough for example). The only thing you need for that would be notes on configuration (unless you have this automated, in which case you don't generally need that, just the notes in your scripts).

So a more important question, to me, is why do you want to back it up in the first place?

Why should I?

Ok, I have a cluster setup, which makes it less likely that all nodes die.
But in case they do, I do get a new server, set it up and get the lxc/vm back from my local disk or cloud copy.

Quick info: you cannot backup the Host server with PBS, only VMs and LXCs.

Edit: there seems to be some ways to send a manual backup of the PVE host to PBS but it seems to be CLI only and I don't think the GUI allows that.

Also, you might want to put the backups in a dedicated partition or drive if you can, so you'd just have to reinstall pbs in case it get bad. I don't know any way to backup pbs, as I don't do that myself, maybe backuppc ?

I don't. But I do sync the backup data to cloud storage.

I have one PBS in local network and another with smaller disk on a cloud vm in case of big failure

Pretty sure PBS doesn't support backing up the PVE host itself. You can find Scripts on github to backup the PVE config

@dimjim

There is this script. Never used so use it at your own risk. It's from Proxmox VE scripts

https://community-scripts.org/scripts/host-backup