This file is an extension to Duplicity 0.7.x that allows it to back up any files in a Qubes OS dom0 (such as VM images) directly to a Duplicity backup directory within a running VM of the Qubes OS system.
Instructions:
- Install Duplicity on dom0.
The usual
sudo qubes-dom0-update duplicityworks well. - Place the file
qubesvmbackend.pyin this repository within the directory/usr/lib64/python2.7/site-packages/duplicity/backends. - You are ready to back up your system to a VM!
Duplicity can be used as the following example shows:
duplicity /var/lib/qubes qubesvm://backupvm/mnt/externaldisk
In this example, Duplicity will back up the directory
/var/lib/qubes into the VM backupvm, taking care to place
the output of the backup into /mnt/externaldisk
(which is, presumably, an external disk that you mounted
within said VM).
Noteworthy: subsequent invocations of the same command will perform incremental backups, such that only the changes between the last backup will be stored, leading to huge disk space savings. Note that incremental backups don't go that much faster than full backups, since Duplicity still needs to read all the source files entirely, before deciding which parts have changed since the last backup. However, disk I/O on the receiving side (the VM) is almost nil for the duration of the incremental backup (except when writing newly-discovered changes to it).
Of course, you can use any Duplicity features, such as PGP encryption and compression.