I'm trying to determine how much data will be written to disk during normal replication.  Consider the following scenario:

1. Source Storage = 1MB Write
2. Source RPA = 1MB Write (or does this write not actually go to disk but stay in memory?)
3. Target RPA = 1MB Write (or does this write not actually go to disk but stay in memory?)
4. Target Storage = 1MB Write
5. Target Journal = 1MB Write

Is this understanding correct?  Please correct if it's wrong.  Thanks.