In a typical configuration, there is at least one trail on the source system and one on the target system. Allocate enough disk space to allow for the following:

• The primary Extract process captures transactional data from the source database and writes it to the local trail. There must be enough disk space to contain the data accumulation, or the primary Extract will abend.

• For a trail at the target location, provide enough disk space to handle data accumulation according to the purge rules set with the PURGEOLDEXTRACTS parameter. Even with PURGEOLDEXTRACTS in use, data will always accumulate on the target because it is transferred across the network faster than it can be applied to the target database.

To prevent trail activity from interfering with business applications, assign a separate disk or file system to contain the trail files. Trail files can reside on drives that are local to the Oracle GoldenGate installation, or they can reside on NAS or SAN devices. In an Oracle cluster, they can reside on ASM or DBFS storage.

See Preparing DBFS for an Active-Active Configuration.