Backup
All relevant data is saved in the SQL database
All relevant runtime configuration is saved in directory
cmsbs-conf
So the minimum requirements to successfully backup your UM instance is a SQL dump and the cmsbs-conf directory.
Recovery
Run installer but do NOT start the UM
Recover cmsbs-conf
Note that server paths may be hardcoded in cmsbs.properties, change if necessary
Recover database
Start UM