Here i am explaining different replication Modes between Sites in the HANA Replication setup.
Synchronous (SYNC) : The secondary system sends an acknowledgment back to the primary system as soon as the data is received and persisted to the log volumes on disk.
Asynchronous (ASYNC): Asynchronous replication, the primary does not wait until the secondary sends an acknowledgement.
Synchronous in-memory (SYNCMEM):The secondary system sends an acknowledgment back to the primary system as soon as the data is received in memory. The disk I/O speed on the secondary system doesn’t influence the primary’s performance.
|Site Distance||Replication Mode|
|< 100 KM||SYNC or SYNCMEM|
|> 100 KM||ASYNC|
For HANA HA setup – within Data-Center we can use SYNC or SYNCMEM Replication Modes between primary and secondary site.
For HANA DR setup– Within Data-center to FAR Data Center ( DR location ) we can use ASYNC Replication Modes between DC to DR location.