A few weeks ago Tiziano Bacocco started a small project to implement a (golang) proxy that allows to store proxmox backups on S3 compatible storage: pmoxs3backuproxy, a feature which the current backup server does not have.

I wanted to have a look at the Proxmox Backup Server implementation for a while, so i jumped on the wagon and helped with adding most of the API endpoints required to seamlessly use it as drop-in replacement in PVE.

The current version can be configured as storage backend in PVE. You can then schedule your backups to the S3 storage likewise.

It now supports both the Fixed index format required to create virtual machine backups and the Dynamic index format, used by the regular proxmox-backup-client for file and container backups. (full and incremental)

The other endpoints like adding notes, removing or protecting backups, mounting images using the PVE frontend (or proxmox-backup-client) work too. It comes with a garbage collector that does prune the backup storage if snapshots expire and runs integrity checks on the data.

You can also configure it as so called “remote” storage in the Proxmox Backup server itself and pull back complete buckets using “proxmox-backup-manager pull”, if your local datastore crashes.

I think it will become more interesting if future proxmox versions will allow to push backups to other stores, too.