Abstract: A data replication management (DRM) architecture comprising a plurality of storage cells interconnected by a fabric. Flexibility in connectivity is provided by configuring each storage cell port to the fabric to handle both host data access requests and DRM traffic. Each storage cell comprises one or more storage controllers that can be connected to the fabric in any combination. Processes executing in the storage controller find a path to a desired destination storage cell. The discovery algorithm implements a link service that exchanges information related to DRM between the storage controllers. The DRM architecture is symmetric and peer cooperative such that each controller and storage cell can function as a source and a destination of replicated data. The DRM architecture supports parallel and serial “fan-out” to multiple destinations, whereby the multiple storage cells may implement data replicas.

Abstract: A system in which data operations for a data replication group are received in-order, and buffered. When the operations are complete, they are stored in a non-volatile memory atomically with a group sequence number. The cache is preferably mirrored. This creates a persistent association between the data operation and the sequence number. After the atomic store is performed in at least one non-volatile cache, the data operation is propagated to another member of the data replication group along with the group sequence number. In the other member, the data operation is cached at least once in a non-volatile cache atomically with the group sequence number. In this manner, the set of group sequence numbers for a plurality of operations forms a continuous ordering of the data operations.

Abstract: A system and method for replicating data between sites in a storage area network in which storage controllers at each site implement storage virtualization. A storage cell is implemented at each site comprising at least one storage controller and a pool of physical storage coupled to the controller. A communication network couples the storage cells. A copy set comprising a logical unit (LUN) of storage, referred to as a member, in each of the storage cells is defined. As operational data transactions are performed against one of the members of a copy set, they are replicated, immediately or after a delay, in each other member of the copy set. As changes are made to dependent attributes of one member of the copy set, the change is replicated in each other member of the copy set automatically. Changes can be made in the independent attributes of each member of the copy set independently of other members of the copy set.

Abstract: A data storage system adapted to maintain redundant data storage sets at a destination location(s) is disclosed. The data storage system establishes a copy set comprising a source volume and a destination volume. Data written to a source volume is automatically copied to the destination volume. The data storage system maintains a data log that may be activated when the destination volume is inaccessible due to, for example, a malfunction in the destination storage system or in the communication link between the source system and the destination system. I/O commands and the data associated with those commands are written to the data log, and after a destination system becomes available the information in the data log is merged into the destination volume to conform the data in the destination volume to the data in the source volume. The data log competes for disk capacity with other volumes on the system, and log memory is allocated as needed.

Abstract: A system and method for replicating data between a plurality of storage locations. Each storage location has a controller with a port to a data communication network and a pool of storage. A logical unit (LUN) of storage is implemented at each storage location such that each implemented LUN comprises a substantially complete replica of the data stored in each other LUN. At least two of the controllers at the plurality of storage locations present their implemented LUN as an active device to the one or more host systems for receiving operational data access requests. Preferably, there are three or more storage locations in the system. Preferably, there are three or more storage locations in the system and each storage location can behave as a source location or a destination location for a particular operational data transaction.