High-Availability Data-Replication buffer
Data replication requires two instances of the database server, a primary instance and a secondary instance, running on two computers.
If you implement data replication for your database server, the primary database server holds logical-log records in the data replication buffers before it sends them to the secondary database server. A data replication buffer is always the same size as the logical-log buffer. For information about the size of the logical-log buffer, see the preceding topic, Logical-log buffer. For more information about how the data replication buffer is used, see How data replication works.