After a painful experience with a crashed engine and a problematic recovery from a backup, I was thinking to create one more engine in standby mode in the same network, that will automatically recover backup files from the active engine on a daily/hourly basis.

This way I'll run recovery tests every day automatically and easily switch in case of engine failure with a DNS record change to the passive engine.

So the main question, is it harmful to have more then one engine alive if only one is been modified? can the standby engine affect the host nodes?