It doesn't matter if this state is obtained from a full or incremental backup, the point is these states should be identical anyway. This means if you extract backup-N files in increasing sequence to get a state from some time ago, any backup-M file (M>0) only expects a valid M-1 state to exist. It is therefore common practice to use /dev/null in its place. When listing or extracting, the actual contents of FILE is not inspected, it is needed only due to syntactical requirements. So it suggests the snapshot file should be updated all the way from the full backup, as if you would need to rebuild backup-N files every time you perform a full backup. To create incremental archives of non-zero level N, create a copy of the snapshot file created during the level N-1, and use it as FILE.
If FILE does not exist when creating an archive, it will be created and all files will be added to the resulting archive (the level 0 dump). FILE is the name of a snapshot file, where tar stores additional information which is used to decide which files changed since the previous incremental dump and, consequently, must be dumped again. Handle new GNU-format incremental backups.
A reasonable doubt, since the manual says: You may wonder if this will keep the old (kept) backup-N files coherent with the new ones. (Note you need to change your working directory from the one with current data to the temporary one, so relative paths stay the same).
Create backup-1 as incremental backup, providing the snapshot file from the previous step.
2 - this is the current backup and will be the biggest because it is a full backup.So the idea is to have a growing list of files like so: I also want to tar the backups because I can also encrypt them before they are uploaded to the cloud. I cannot use hard-links because the tar files will ultimately be uploaded to a cloud provider that doesn't maintain/understand links and what not. I want mimic that functionality with tar. In the past I have used rsync and hard-links to make backups where backup-0 is current state and each backup-x folder has the files that were specific to that backup. , backup-x with the changes in order of the backups. The end result is a backup-0 file that has the first full back-up and then backup-1, backup-2.
I am somewhat familiar with how to use tar's -listed-incremental flag to take incremental backups.