make a backup of
- all local , central, profiler Databases
- cms, audit databases
- input and output file repository
- You need not stop any services the installer will restart all services any ways.
- run setup on all machines in a clustered setup where one or more DS components are installed.
repo version does not upgrade between DS 4.1 SP1 and SP3 so you do not have to really run repo manager to upgrade the repos after sp3 install.