in the past with other distros I have used with success rsync to replicate exactly my servers with configurations, services information, data.
Honestly I don't know if it is possible to replicate a NethServer in real time but could be also useful with a time offset of, for example, 15 minutes?
In my case a script had to do some additional operations before starting rsync such as stopping services and so on.
What do you think about this method?
Please let me know, it's a very interesting argument and useful think in real world.