To set up copying of logs to /var/log/dirvish, alter
/etc/dirvish/dirvish-cronjob so that the main body appears as follows:

mount_output="`/usr/local/sbin/ext-mount /mnt/backup`" || exit 1

/usr/sbin/dirvish-expire --quiet && /usr/sbin/dirvish-runall --quiet
rc=$?

# pass the UUID and drive description to after-dirvish as separate args
read uuid desc <<< "$mount_output"
/usr/local/sbin/after-dirvish $uuid "$desc"

umount /mnt/backup

exit $rc



NOTES:
Perhaps applies specifically to Debian.

Replace /mnt/backup with your backup mount point (it is recommended that the
Dirvish bank be a subdirectory of the external HDD filesystem so that an error
will be detected if this is not mounted).


TO-DO:
  + Average byte count from multiple log.gz and warn if HDD has less than
    2 * count bytes free
  + provide option to use all vaults rather than those listed in Runall setting
    (the former is the fallback action if the latter isn't set)
  + update the drive's consecutive backup count
  + warn (via the admin address) if the drive's consecutive backup count is
    greater than <max_backup_count> times in a row
  + log to syslog
  + update the drives recently used list
  + unset <drive_to_swap> if it refers to the current drive