These are the conditions in which Exchange’s Replication service will truncate the committed log files in Exchange:
Exchange 2010 & 2013
- The log file must have been successfully backed up, or circular logging must be enabled.
- The log file must be below the checkpoint (the minimum log file required for recovery) for the database.
- All other lagged copies must have inspected the log file.
- All other copies (not lagged copies) must have replayed the log file.
Exchange 2013 uses quite a big checkpoint depth (100MB), it’s usual to find a hundred or more transaction logs even when circular logging is enabled and the database is essentially quiescent. It’s far removed from the five or six transaction logs that a standalone database enabled for circular logging might use.