wish: ship with example systemd config files

[markstos]

A number of popular Linux distributions have standardized on systemd. systemd includes an alternative to cron in the form of systemd timers. There are some advantages to using systemd timers and it's certainly of interest to use them with rsnapshot for an admin already managing a number of other services running on systemd timers.

It seems right now at least Ubuntu and Arch don't ship any systemd timer files as examples for rsnapshop, leading to duplicated documentation and effort to get this setup as interested users each figuring this out on their own.

It would be helpful if rsnapshot shipped some example systemd timer and service files for those who wish to use them instead of cron.

The Rsnapshot page on the Arch wiki is one source of examples.

I've also documented how I setup rsnapshot with systemd on Ubuntu on my own blog.

Before when I used rsnapshot with cron, I was always getting output in my email which I didn't want from successful runs. I'm sure there was a way to only get emailed on failure using Cron and still have the logs somewhere, but it always remained an annoyance. systemd makes it fairly easy to have both detailed logs from the backup process and still get emailed when there's a failure.