Remote Copy replication modes

Replication mode	Difference between other modes
Synchronous: Synchronous mode Remote Copy groups stay synchronized as long as the replication links remain up and available.	Data concurrency is greater than in asynchronous periodic mode, but host write I/O response times might be higher than in asynchronous periodic mode. RPO is 0.
Asynchronous periodic: Asynchronous periodic mode Remote Copy groups resynchronize at specific intervals using snapshots. Asynchronous periodic is also known as periodic.	Host write response times is better than in synchronous mode, but data is not always synchronized. For properly sized replication links, the RPO is two times the replication period selected for the Remote Copy group. For example, using the minimum replication period of 30 seconds, the minimum RPO is 1 minute. TIP: A 1 minute RPO is supported in HPE Primera OS 4.2.