When MARS does a restore for an archive, think of it like loading a ghost image on a Windows server. It restores EVERYTHING, including the configuration, event data, and even the OS (optional). So, the archive acts like a snapshot of the system at that time.
But to do that, it has to replace the current information. Thus, the reason data can't be restored on a single box, while still operating normally.
From the MARS "Initial Configuration And Upgrade Guide":
"The reason to use a separate appliance to study old data is that you must restore the period data to the appliance, and the restore re-images all configuration and event data based on the archive settings for the defined period."
And later in the same guide:
"A restore operation does not allow for incremental restores of event data only. It always performs a complete reimage of the harddrive in the target appliance."
Hope that helps.
