- Back ups are stored on a separte disk which is rarely used. (I might further replicate them in the future, but there has to be a balance between security and fault tolerance.)
- Every two months a full dump of /etc, /home, /var/www and /var/lib/ejabberd is done.
- Every two weeks this dump is updated with changes.
- Two full backups are to be kept (in case one of them gets corrupted), older ones are removed.
As you can see it may take quite some time before a file that you remove will completely disappear from the back ups (it can take as long as four months). But the back ups are only readable by root (the system administrator), and thus by checking the sudo log you can determine that your files have not been extracted from the back ups.
Back ups are made with the straightforward hdup program and are launched automatically from cron.