Abstract: Auto-trespass can be at least temporarily disabled subsequent to an automatic failover. The automatic failover exchanges roles between an active path and a passive path, such that the passive path becomes the active path and vice versa. By disabling auto-trespass, hosts that are unaware that the automatic failover has occurred will not trigger another failover when those hosts attempt to perform I/O operations via the formerly-active path. This can reduce performance decreases that would otherwise occur due to the active role being traded in a “ping-pong” manner between the paths.

Abstract: One method of updating a change track map involves resetting a mirror recovery map for a data volume. Just before the mirror recovery map is reset, a change track map for the data volume can be updated, using the mirror recovery map. The mirror recovery map can be reset by a data element of a data processing system, while the change track map can be updated by a control element of the data processing system.

Abstract: Systems, methods, apparatus and software can combine information about host access to virtualization functionality and virtualization functionality access to storage, use this information in decisions pertaining to high availability of virtualization in an SAN. Upon detection of the partitioning of a SAN fabric, accessibility information is gathered. That information is analyzed to uncover potential failover scenarios, orchestrate such failovers, and in some cases select best case solutions from among several possible solutions based on access prioritization criteria (e.g., defined priority, maximum access, maximum I/O, etc.).

Abstract: A method involves: executing an application on a cluster, which includes several nodes; and, subsequent to the cluster being partitioned into several sub-clusters, a first one of the sub-clusters executing a first one of the applications and a second one of the sub-clusters being capable of executing a second application. The first sub-cluster executes the first one of the applications after either determining that no other sub-cluster includes nodes that are part of the logical cluster that runs that application or after winning ownership of the logical cluster that runs the application. In a competition for ownership of a logical cluster, the winning sub-cluster is selected based on application-specific information, which is specific to the application that runs on that logical cluster.

Abstract: Systems and methods for storage area network switch port failure recovery. A system may include several hosts, storage devices and a storage area network (SAN) switch. The SAN switch may include several ports, where each host is coupled to a respective host port and each storage device is coupled to a respective storage port. The SAN switch may also include virtualization logic configured to map several of the storage devices as a volume presented to the hosts via the respective host ports, and an input/output (I/O) tracking mechanism configured to store information about write operations in progress at each of the ports. In response to a failure of a given port occurring while write operation(s) to the volume received via one or more of the respective host ports are in progress, the SAN switch may be configured to initiate consistency recovery of the volume using the stored information.

Abstract: A method and system for mirror storage element resynchronization in a storage virtualization device is disclosed. According to one embodiment of the present invention, a read operation on a region of a data volume is received at a first module of a first storage virtualization device where the data volume is associated with at least a first mirror storage element and a second mirror storage element, a state indicated by a bit corresponding to the region of the data volume within a first synchronization map is determined in response to receiving the read operation, the read operation is processed using the first module if the bit is determined to indicate a first state and using a second module of the first storage virtualization device if the bit is determined to indicate a second state.