The HSQLDB database is stored in a subdirectory of the alf_data directory (the directory pointed to by the dir.root property) by default, so you shouldn't need to do anything special to back it up - simply back up the entire alf_data directory and you're done.
Obviously backup and restore is something you want to test carefully - nothing worse than assuming that your backups have worked only to find out that they haven't! :wink:
Also please note that HSQLDB is not designed for production use - if your repository contains content that is important enough that it requires backing up, I would strongly encourage you to move to a "real" database.
