If you use the Proxmox Backup Server to perform updates of Proxmox and the virtualizations running there, setup is quite simple. Unlike other backups, such as borg backup, the Proxmox Backup Server does not perform deduplication during the backup itself.
After setting up the backup, everything worked fine for quite some time. But then one day I received error messages saying that there was no more space available on the backup server. I was surprised, because I knew that the Proxmox backup server also deduplicates data. So it shouldn’t have used up much space, and above all, it shouldn’t have been constantly filling up.
So I searched for a while and then found out that you have to configure deduplication and retention policy on the backup server. To do this, you have to create a “Prun & GC Job.” To do this, open the backup server GUI via the URL and go to Datatastore/<name of the datasores>. In my case, this is Backup.
There, under Garbage Collection Job, you need to set when this should run. You should also create a “Prune Job” by clicking on “And.” It should look something like this:
After that, you should no longer have any space problems. If you want, you can also receive an email report about the cleanup.
