Occasional backup failures

[Zephrant]

I thought that setting a BW limit of 1G on the backup server helped, but it's still doing it after another day or two.
Oddly, when I backup to a NFS mount (NetApp) I get no errors. The same VMs backed up to a Proxmox backup server gets timeouts.
Both the NFS and the Proxmox backup server have dual 40g ports, so bandwidth is similar, but the Proxmox backup server is lower in disk performance.