Tape backup and media sets/pools

[aaronc_rae]

I am new to proxmox and its backup system and am curious how the backup systems works with tapes.

The company I work for is a fan of WORM tapes for ransomware protection.

Currently for our physical servers, we use Veeam and it creates a full backup every month and daily incrementals that get written to tape immediately after the main job completes. 2 months fit on one LTO8 tape and occasionally a restore chain spans 2 tapes if a month ends up spanning a tape change.

I got a new LTO9 drive and added it to our proxmox setup to test out how it works.

Integration and setup was flawless and I had a job setup in minutes.

However I am curious about what is actually written to tape and if it is possible to sort of duplicate the functionality of veeam's "monthly full backup".

PBS's de-duplication is far more efficient for storing our file system data (because duplication) and I am not filling a tape in a month(or 3 or 4 or more), the "incremental" backups of proxmox seem to write just a few gigabytes/day to the tape.


To boil things down, i wan to know:
Is it possible to start a new full copy of the data store monthly to the same tape? or at the very least start a new copy of the full dataset every tape? I dont quite understand the retention and allocation policies for this purpose. I set the allocation policy to monthly and the retention to keep and it has set the tape to "full" after writing only 33% to the tape.

Thank you in advance.

 

[dcsapak]

Is it possible to start a new full copy of the data store monthly to the same tape? or at the very least start a new copy of the full dataset every tape? I dont quite understand the retention and allocation policies for this purpose. I set the allocation policy to monthly and the retention to keep and it has set the tape to "full" after writing only 33% to the tape.

with pbs one 'backup unit' (which is restorable) is a 'media-set' which can consist of multiple tapes (if necessary)
the allocation/retention policy describe when a new media-set is allocated and for how long it won't be overwritten.
each time a media-set is started it will begin on a new tape regardless of how full the existing ones are

so if you use monthly allocation policy, each month you start a new media-set

there is no way to store multiple "full" backups onto one tape (also it does not make sense IMHO since it only wastes space)

if you want to have multiple copies of the data, you should have multiple media-sets, even if they don't use the full capacity of the tapes