You can backup your system with ease and then restore to the same or another PC, with the same Resilient Server version installed.
For backing up your persistent data (which are, after all, the diffs from the stock installation), just tar the rw folder within the fourth (persistence) partition and take note of the running kernel version (the contained kernel modules must match the running kernel).
Restore is a two phase process:
1. Make the system’s kernel match the kernel version you used for your backed system.
2. Untar the rw.tar file as the rw folder in the persistence partition and reboot.
The persistence partition is already unlocked and mounted on the running system in /run/live/persistence/sdX4.