To manage the amount of disk space used up on your backup drives and prevent it from getting filled up it is important to configure a retention policy for each of your VMs backups.
To do this, simply go to [Setup] > [Backup Settings] > [Retention Policy]
You will notice that the retention policy for the primary backups is marked in blue , while the offsite backups are marked in orange . This means that a VM can have a different retention policy for the primary and for the offsite copies.
To add a VM to the retention policy, simply drag and drop the VMs from the left hand side menu.
To create a new custom retention policy, click on [Add New] button in the appropriate section.
To remove a VM from a particular retention policy, click the [x] icon next to it. This will clear the retention policy for that VM and set it to 'Never Delete'.
You can also configure the retention policy to keep Weekly, Monthly and Yearly backups instead of deleting all old versions that go beyond your retention policy. This is further documented here.
Choosing the right setting for my Retention Policy?
We recommend that you start with a slightly lower option (let's say you're setting it to 1 month) and then take it from there. This will allow you to properly gauge on what your usage really looks like on a day-to-day basis. With our Augmented In-Line Deduplication and compression you should see considerable savings from your backup storage.
Once you've reached that 1 month from the first time you started taking backups with VM Backup, and you see that you still have a sizeable amount of free space leftover, go ahead and increase it accordingly.
Naturally, keep in mind that if you're going to configure GFS Archiving, your retention policy needs to accommodate for the extra storage space that will eventually be used up by the archived backups.
Also, always ensure that you have enough space for future-proofing.