The maximum size of the FDTC data file is set to a default value of 200 MB and can be customized by setting the diagnosticDataCollectionDirectorySizeMB option. By embedding the router, the MongoD process will produce diagnostic data for both router and shard services, requiring additional space to maintain the retention we have today.

The goal of this ticket is to change the default value of the diagnosticDataCollectionDirectorySizeMB option on MongoD to 400 MB when the built-in router is enabled and leave 200 MB otherwise.