Which replication modes keep the primary system waiting until a timeout is exceeded when the secondary system is not available?

The correct choice is the replication mode that ensures data consistency by requiring the primary system to wait for acknowledgment from the secondary system before it can proceed. In this context, the mode that keeps the primary system waiting until a specified timeout is exceeded when the secondary system is not available is characterized by its synchronous behavior, even if it leverages memory for temporary data storage.

SYNCMEM indicates that the primary system sends data to the secondary system and holds off on further processing until it receives confirmation that the data has been successfully written to the secondary system’s memory. This ensures that no data is lost during the replication process and that the primary system can maintain a consistent state in line with the acknowledgments received from the secondary system.

In contrast, other modes like ASYNC allow the primary system to continue processing without waiting for confirmation from the secondary system, which could result in data inconsistencies if the secondary system becomes unavailable. SYNC is similar to SYNCMEM in its reliance on acknowledgment but may not specifically involve memory-based operations. LOGSYNC may pertain to the logging behavior rather than waiting for confirmation in the same way.

Therefore, the replication mode that involves synchronously waiting for the secondary system's acknowledgment and potentially keeps the primary system waiting until timeout is indeed