As has already been suggested ... non prime time, but make it known to all users that such maintenance is necessary and will happen at 2:00AM (if that's when you schedule it) everyday - period. Not responsible for lost work during the scheduled maintenance window time frame.
The sensitive things would be DB backup as well as an rsync of data directory. The code directory backup could be made at any time ... it should be static stuff ... ie, the same files.
'spirit of sharing'. Ken