The LOG_REPLICATION setting in notes.ini specifies the level of logging of replication events performed by the current server, where:
0 = Do not log replication events
1 = Log that a database is replicating
2 = Log information about each replicated database
3 = Log information about each replicated document (both design and data documents)
4 = Log information about each replicated field
5 = Log summary information about replication events
LOG_REPLICATION for further information.