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 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 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.

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 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: One application of clustered computer systems is to support failover of applications and shared resources. Another is to support scalable or fault-tolerant distributed applications. The present invention utilizes a higher-level clustering mechanism (a multi-cluster) overlayed on top of multiple underlying clusters (subclusters) to extend their capabilities. In the described embodiment, subclusters supporting application and shared resource failover across a smaller number of nodes is overlayed with a multi-cluster supporting a larger number of nodes. The multi-cluster manages cluster-level communication among nodes, and the subclusters directly manage only the shared device and application resources which they are permitted to control. It is possible to move resources between nodes which reside in different subclusters. The multi-cluster layer also externalizes interfaces similar to those of the subclusters, providing application compatibility.

Abstract: A clustered computer system provides both speed and reliability advantages. However, when communications between the clustered computers is compromised those same computers can become confused and corrupt database files. The present method and apparatus are used to improve the management of clustered computer systems. Specifically, the system expands the number of nodes available for failover conditions.

Abstract: A method in a computer for handling a network partition of a clustered computer system, wherein the computer is part of a number of computers located within the cluster. Data is periodically written into a data structure in a shared resource, wherein the data provides a status of the computer and wherein a data structure is associated with each cluster node. Monitoring for a partition of the cluster is performed. All data structures located in the shared resource are read in response to detecting a network partition of the cluster. A determination is made as to whether the computer is in the preferred partition, one containing the largest number of computers or is otherwise determined to be viable for continued operation. Should the computer determine that it is not a member of a preferred or otherwise viable partition, it must relinquish access to shared cluster resources requiring mutually exclusive access, such as a database on a shared disk volume.

Abstract: A support mechanism for holding a water skier to a water skiing tow bar utilizing a harness capable of being connected to the water skier. The harness includes an element which extends a certain distance relative to the water skier, preferably along the front portion of the water skier. A link connects to the element and may be slidable or movable along the certain dimension of the element. A line is fixed to the movable element and possesses pre-determined degree of flexibility to wrap about a tow bar and alleviate the effort expended by a skier holding on to the tow bar.