The logging facility in SimFactory is supposed to keep track of all actions performed on a simulation. That is, there needs to be exactly one log file per simulation. It is not necessary to have a log file within the Cactus source tree, since this file could go away at any time, and is not connected to any simulation.
The log file should be created when a simulation is created. Only important actions -- actions that potentially modify the state of the simulation -- should be logged. For example, if a new restart is created, or if a restart is stopped, or if a simulation is archived, then this should be logged. If a simulation is only examined, then this should not be logged.
Python has a convenient logging facility. This should be used if possible.