Backup and Restore - Proxmox VE
https://pve.proxmox.com/wiki/Backup_and_RestoreIt works by performing a Proxmox VE live backup, in which data blocks are copied while the VM is running. If the guest agent is enabled ( agent: 1) and running, it calls guest-fsfreeze-freeze and guest-fsfreeze-thaw to improve consistency. A technical overview of the Proxmox VE live backup for QemuServer can be found online here.
Storage: NFS - Proxmox VE
https://pve.proxmox.com/wiki/Storage:_NFSThe NFS backend is based on the directory backend, so it shares most properties. The directory layout and the file naming conventions are the same. The main advantage is that you can directly configure the NFS server properties, so the backend can mount the share automatically. There is no need to modify /etc/fstab.