the rdiff handler uses rdiff-backup to make remote, incremental backups of the filesystem.

the ninjahelper is good at creating initial .rdiff files for you.

here is an example file, /etc/backup.d/action.rdiff:

######################################################
## source section
## (where the files to be backed up are coming from)

[source]

# an optional subdirectory below 'directory' (see [dest])
label = thishostname

# only local type is currently supported
type = local

# how many days of data to keep
keep = 185

# files to include in the backup
# (supports globbing with '*')
include = /var/spool/cron/crontabs
include = /var/backups
include = /etc
include = /root
include = /home
include = /usr/local/bin
include = /usr/local/sbin
include = /var/lib/dpkg/status
include = /var/lib/dpkg/status-old

# files to exclude from the backup
# (supports globbing with '*')
#exclude = /home/*/.gnupg

######################################################
## destination section
## (where the files are copied to)

[dest]

# remote or local? If local, you dont need to specify a host below
type = remote

# the machine which will receive the backups
host = backuphost

# put the backups under this directory
directory = /backups

# make the files owned by this user
# note: you must be able to ssh backupuser@backhost
# without specifying a password 
user = backupuser