backup-prepare

What is does?

You give it a directory and it will create a folder of name current date and time (YYYYmmdd-HHMMSS) inside and links latest to its location. When the script is executed next time, the whole content of latest is hard linked into the newly created folder, so that it does not take additional disk space.

Also, one can use -b param to take use of btrfs snapshots instead of hard-linking everything.

After this is done, you can run rsync, that will incrementally change only modified files and the rest is kept unchanged. The effect is that in the end you have multiple full backups which take only a fraction of space that it would if you were to copy all content.

How to install (or update)

sudo wget 'https://raw.githubusercontent.com/esoadamo/backup-prepare/main/backup-prepare' -O /usr/bin/backup-prepare
sudo chown root:root /usr/bin/backup-prepare
sudo chmod 755 /usr/bin/backup-prepare

How to use?

Usage: ./backup-prepare [-h] [-f] [-d] [-m NUM] action dir
-h      ... prints this message
-f      ... forces actions, does not ask for deletion confirmation
-m NUM  ... keep max last NUM of backups, delete older
-b DIR  ... use btrfs mode and save snapshots into given directory
action  ... prepare | finish | delete
            - prepare  ... creates new directory and in-progress link
            - finish   ... changes latest to in-progress and deletes old backups (in max backups is specified)
            - delete   ... deletes old backups (in max backups is specified)
dir     ... directory in which the backup will be created