Proxmox allows a lot of powerful options when it comes to shared file systems, but nothing could be simpler than using sshfs and adding the directory to Proxmox as a storage option for backups, VMs and ISOs.

In my case, I have 2 Proxmox servers and a 3rd server running Ubuntu which I would like to store backups on.

I my 2 Proxmox servers which are an i5 and an i7 from SerweryDedyKowane.pl which are both hosted on the same network in Poland, and the backup server is an i5 V-Dedi from Wishosting which is hosted in Canada.

Here's what I did:

First, I set up sshfs to point to the storage on the backup server.

In this example, I have set up sshfs on both Proxmox servers. So, on each Proxmox server there is a folder called /mnt/remotebackup which is where I'd like to store my backups.

In the Proxmox UI, we need to click on Datacenter then click on Storage. From there, we need to Add a Directory.

Now that we have that set up, on BOTH Proxmox servers (In my case, it actually copied across by itself so you may only need to do it once, but if not, do it on all the other Proxmox servers) - we can start using the storage.

To verify that backups will work, I will select a VM, and then go to the Backup tab and click on Backup Now - on this screen make sure that Storage is showing the new storage we made, in my case it's called remotebackups

Go ahead an make a backup, it'll take a little while depending on the size of the VM but it will be stored on the remote server.

Neat eh?