Related to FS#3849, there are two other fields that cause errors when the backup job is run on a subdirectory. My understanding is that a "subdirectory" is defined as backing up any directory within a partition, as opposed to backing up the partition itself. So, for example I want to back up /var/spool/mail, which is a subdirectory of the /var partition.
The first problem is setting the dump level. If it is set to anything other than 0 (Full backup), then the backup job fails with the following error:
DUMP: Only level 0 dumps are allowed on a subdirectory
DUMP: The ENTIRE dump is aborted.
The second problem is choosing to update the /etc/dumpdates file. If this is set to yes, then the backup job fails with the following error:
DUMP: You can't update the dumpdates file when dumping a subdirectory
DUMP: The ENTIRE dump is aborted.
These two problems combined caused my backup to fail two nights in a row. It would be nice if the Webmin module could detect these potential errors when the job is being configured and display an error right away, rather than having to wait for the backup to run and fail at the next scheduled time.
Lastly, the help text for these two items is a bit lacking or incorrect. The help text for the dumpdates option says the following:
When this option is enabled, the date, time, source and destination of the backup will be recorded in human-readable form in /etc/dumpdates.
However, my dumpdates file only displays lines like this:
/dev/sda5 0 Sun Apr 13 00:00:17 2008 -0400
As you can see, they don't show the destination, and they don't show the source in a user-friendly format (i.e. device rather than mounted partition name). Instead, I would suggest something like the following (paraphrased from the dump man page):
This option can only be enabled when backing up an entire filesystem. When enabled, the source filesystem device name, level, date and time of the backup will be recorded in human-readable form in /etc/dumpdates. There may be only one entry per filesystem at each level. This option is useful when using the dump -W command-line option to display the most recent dump date and level of each filesystem.
As to the help text for the dump level option, I would just add a point to say that the dump level must be set to (Full backup) when backing up a subdirectory (not an entire filesystem).
Thanks,
Alan