That is not working automatically. If you have set 1 to the 5th field in
/etc/fstab that means nothing yet. First the utillity
dump must exist on the system (nowadays it's most probably not installed). Second,
dump must be called manually or at least via
dump was used to make backups on tape drives. An advantage of
dump was the fact that it operated below the filesystem, so when backuping the access time of files and folders was not changed.
dump can also print the backup to stdout. So it was also used to pipe the output trough an ssh connection to a backup server.
But, take care when backuping with
dump can safely be used against unmounted and read-only filesystems. On mounted filesystem that are not idle, I wouldn't recommend