On a gcloud debian vm instance, I would like to create full backups and rotate them, e.g.
That is, each daily would get over-written every seven days, weekly each month, monthly each year, and yearly kept "forever".
I thought I could do this with a snapshot, but there seems to be no provision in the disks snapshot command to force a full snapshot without deleting existing ones.
The other option seems to be disk images, but those appear to be literal images, taking up a full disk's amount of space which seems particularly wasteful.
One possibility would be to delete all snapshots, create a snapshot, copy it to another disk, then delete it. However, I don't see any way to copy a snapshot.
Another would be to copy a machine image someplace and compress it; maybe it is already compressed? But again, I see no way to copy / manipulate a machine image.
Surely this is possible? Any suggestions on other options?