* Edit the file /etc/netatalk/AppleVolumes.default and replace this path /var/hda/files/amahi-time-machine by the path of the folder where the backups should go.

Note that Time Machine will ask for a user and a password. This user and password you provide must have write access to the folder you set up.

By default, Apple's Time Machine software will grow the backup size to use all available disk space. To artificially limit this, do the following.

On the line that begins '/var/hda/files/amahi-time-machine', add 'volsizelimit:XXXX' AFTER 'options:tm', where XXXX is the artificial limit in MiB.

NOTE: do not do this while a backup is running. The way Apple's Time Machine software works requires more disk space than the size of the backup available. It is usually best to put a volume size limit in place before the first backup is created.