Currently MPMissions is always a subfolder of the main game. Defining to use a mission in a different directory / use a different directory as mpmissions, which would be even on a different drive would improve things drastically.
As example: I create a 4GB RAM Drive for DayZ Server, So worldsaves (in storage_X) get full speed.
Most of that holds the DayZ Installation, even tho it would suffice to put it on a harddrive.
Logs will soon eat up a lot of that diskspace as well.
If I could advice the server however to load missions from a different folder / Drive, i could separate the game from storage and profile folders.