STORAGE SYSTEMS CONFIGURED FOR STORAGE VOLUME ADDITION IN SYNCHRONOUS REPLICATION USING ACTIVE-ACTIVE CONFIGURATION

An apparatus in one embodiment comprises at least one processing device comprising a processor coupled to a memory. The at least one processing device is configured to identify a storage volume to be added to a first consistency group of a first synchronous replication session between a first storage system and a second storage system in an active-active configuration, to create a second synchronous replication session for the added storage volume between the first storage system and the second storage system, and to merge the first and second synchronous replication sessions responsive to one or more designated criteria. The second synchronous replication session is illustratively configured to be fully independent of the first synchronous replication session. Merging the first and second synchronous replication sessions responsive to one or more designated criteria illustratively comprises merging the first and second synchronous replication sessions responsive to the second synchronous replication session reaching a specified steady state.