Take snapshot(if there is change) and retains snapshots.
not detect all types of changes, for example: deleted files.
/mnt/hdd1 (volume root directory)
+-- @workspace (subvolume root directory)
\-- snapshots (directory)
\-- workspace (directory)
+-- @workspace_autosaved_2020.04.22_12.23.44 (snapshot of subvolume "@workspace")
+-- @workspace_autosaved_2020.04.22_12.26.29 (snapshot of subvolume "@workspace")
+-- workspace_autosaved_latest (symbolic link of latest snapshot of "@workspace")
Schedule to run btrfs-autosnap
with cron
*/15 * * * * root /usr/local/etc/btrfs-autosnap -c 8 workspace
-c
option is retainning count