Store four (4) "Mondays" on a single Monday tape... and so on.

[mindmachine]

We have a tape for each day of the week (Monday, Tuesday, etc.) and use a single LTO-6 drive.
I've set up media pools for each day (Monday, Tuesday, and so on).

The size of the CT being backed up is roughly 250GB. I aim to restore the entire CT from a single tape in the event of a disaster.

I want to ideally store at least four (4) "Mondays" on each Monday tape, four "Tuesdays" on the Tuesday tape, four "Wednesdays" on the Wednesday tape, and so on.

Is this possible and is it accomplished by setting the Retention period to 4 weeks?

I am slightly confused by the Allocation Policy vs Retention Policy. I have the Allocation Policy set to 01:30 (Daily), but my confusion stems from the option of "Continue" and "Always" as I interpret the allocation policy to be when or how often to back up a data store.

 

[dcsapak]

hi, did you already check out the docs? : https://pbs.proxmox.com/docs/tape-backup.html#media-pools

the allocation policy determines when a new media-set is allocated, so if you want multiple weeks on a single media-set you should e.g. use something like montly instead of daily
the retention policy controls how long media-sets are not overwritten and valid (see the docs for how that is calculated)

an allocation policy of 'continue' never allocates a new media-set and will continue it forever
and 'always' will allocate a new one on every tape backup

 

[mindmachine]

Not only have I checked out the documentation, but I'm one of those who print out the entire manual, lovingly place it into a nice binder, admire the high quality of the writing, and often reference Proxmox documentation like a prized ancient artifact. In other words... Proxmox documentation has always been excellent. However... I had difficulty clarifying the "allocation" policy vs "retention" policy, but your reply helps make sense of it for me. Thank You.

 

[dcsapak]

great

anything specific that i mentioned or described differently than the documentation that would have cleared it up better? (so i can update the docs with a possibly better description)