Abstract: An example method of controlling a storage system that includes a replication group. The method may include adding a virtual volume to the replication group by storing a journal entry for the virtual volume at a source site. The journal entry may include: metadata for hooking the virtual volume to a corresponding replica volume; and data indicating a status of the virtual volume. The method may further include sending a message to a replica site instructing it to create the corresponding replica volume for the virtual volume and store a replica journal entry for the replica volume. The method may also include determining whether to set the status of the virtual volume to pending admittance or newly admitted based on whether the replica site was able to successfully create the replica volume and store the replica journal entry.

Abstract: Examples include volume and snapshot replication. In some examples, a user-initiated snapshot of a volume at a source array may be created, wherein the user-initiated snapshot has a pending status and the volume is a member of a set of volumes in a replication group. A synchronization snapshot may be created of the volume at a periodic synchronization time. The synchronization snapshot may have a pending status. Each snapshot of the volume may be stored at the source array and each snapshot may be recorded via a representative entry in an original snapshot list. The volume may be incrementally replicated to a target array such that the target array has a replica of the volume at the source array via a replication engine.

Abstract: An example method of controlling a storage system that includes a replication group. The method may include adding a virtual volume to the replication group by storing a journal entry for the virtual volume at a source site. The journal entry may include: metadata for hooking the virtual volume to a corresponding replica volume; and data indicating a status of the virtual volume. The method may further include sending a message to a replica site instructing it to create the corresponding replica volume for the virtual volume and store a replica journal entry for the replica volume. The method may also include determining whether to set the status of the virtual volume to pending admittance or newly admitted based on whether the replica site was able to successfully create the replica volume and store the replica journal entry.

Abstract: Examples include volume and snapshot replication. In some examples, a user-initiated snapshot of a volume at a source array may be created, wherein the user-initiated snapshot has a pending status and the volume is a member of a set of volumes in a replication group. A synchronization snapshot may be created of the volume at a periodic synchronization time. The synchronization snapshot may have a pending status. Each snapshot of the volume may be stored at the source array and each snapshot may be recorded via a representative entry in an original snapshot list. The volume may be incrementally replicated to a target array such that the target array has a replica of the volume at the source array via a replication engine.