Abstract: Provided are an apparatus and method for managing data storage. A first log structured array stores data in a storage device. A second log structured array in the storage device stores metadata for the data in the first log structured array, wherein the second log structured array storing the metadata for the first log structured data storage system is nested within the first log structured array, and wherein the first and second log structured arrays comprise separate instances of log structured arrays. Address space is allocated in the second log structured array for metadata when the allocation of address space is required for metadata for data stored in the first log structured array.

Abstract: Provided are an apparatus and method for managing data storage. A first log structured array stores data in a storage device. A second log structured array in the storage device stores metadata for the data in the first log structured array, wherein the second log structured array storing the metadata for the first log structured data storage system is nested within the first log structured array, and wherein the first and second log structured arrays comprise separate instances of log structured arrays. Address space is allocated in the second log structured array for metadata when the allocation of address space is required for metadata for data stored in the first log structured array.

Abstract: Provided are an apparatus and method for managing data storage. A first log structured array stores data in a storage device. A second log structured array in the storage device stores metadata for the data in the first log structured array, wherein the second log structured array storing the metadata for the first log structured data storage system is nested within the first log structured array, and wherein the first and second log structured arrays comprise separate instances of log structured arrays. Address space is allocated in the second log structured array for metadata when the allocation of address space is required for metadata for data stored in the first log structured array.

Abstract: Provided are an apparatus and method for managing data storage. A first log structured array stores data in a storage device. A second log structured array in the storage device stores metadata for the data in the first log structured array, wherein the second log structured array storing the metadata for the first log structured data storage system is nested within the first log structured array, and wherein the first and second log structured arrays comprise separate instances of log structured arrays. Address space is allocated in the second log structured array for metadata when the allocation of address space is required for metadata for data stored in the first log structured array.

Abstract: Provided are an apparatus and method for managing data storage. A first log structured array stores data in a storage device. A second log structured array in the storage device stores metadata for the data in the first log structured array, wherein the second log structured array storing the metadata for the first log structured data storage system is nested within the first log structured array, and wherein the first and second log structured arrays comprise separate instances of log structured arrays. Address space is allocated in the second log structured array for metadata when the allocation of address space is required for metadata for data stored in the first log structured array.

Abstract: A storage control system adapted to operate as a remote copy pair by communicating between a primary and a secondary of the remote copy pair comprises a selector for selecting writes to be placed in a batch based on one or more criteria, a sequence number requester for requesting a sequence number for the batch, and a sequence number granter for granting a sequence number for the batch. The storage control system also comprises a batch transmitter for transmitting the batch to the secondary, a permission receiver for receiving a permission to write the batch from the secondary, and a write component responsive to the permission receiver to write the batch to completion, wherein the secondary is responsive to the completion to grant a further permission to write for a further batch.

Abstract: A storage control system adapted to operate as a remote copy pair by communicating between a primary and a secondary of the remote copy pair comprises a selector for selecting writes to be placed in a batch based on one or more criteria, a sequence number requester for requesting a sequence number for the batch, and a sequence number granter for granting a sequence number for the batch. The storage control system also comprises a batch transmitter for transmitting the batch to the secondary, a permission receiver for receiving a permission to write the batch from the secondary, and a write component responsive to the permission receiver to write the batch to completion, wherein the secondary is responsive to the completion to grant a further permission to write for a further batch.

Abstract: A storage control system adapted to operate as a remote copy pair by communicating between a primary and a secondary of the remote copy pair comprises a selector for selecting writes to be placed in a batch based on one or more criteria, a sequence number requester for requesting a sequence number for the batch, and a sequence number granter for granting a sequence number for the batch. The storage control system also comprises a batch transmitter for transmitting the batch to the secondary, a permission receiver for receiving a permission to write the batch from the secondary, and a write component responsive to the permission receiver to write the batch to completion, wherein the secondary is responsive to the completion to grant a further permission to write for a further batch.

Abstract: A storage control system adapted to operate as a remote copy pair by communicating between a primary and a secondary of the remote copy pair comprises a selector for selecting writes to be placed in a batch based on one or more criteria, a sequence number requester for requesting a sequence number for the batch, and a sequence number granter for granting a sequence number for the batch. The storage control system also comprises a batch transmitter for transmitting the batch to the secondary, a permission receiver for receiving a permission to write the batch from the secondary, and a write component responsive to the permission receiver to write the batch to completion, wherein the secondary is responsive to the completion to grant a further permission to write for a further batch.

Abstract: Failover in a clustered system is managed. The clustered system includes sub-clusters connected with one another by a first set of links. Each sub-cluster includes nodes connected with one another by a second set of links. At least one of the second set of links is used to determine that a suspect node within a same sub-cluster has stopped. In response, a lease relinquish message is transmitted on behalf of the suspect node.

Abstract: Provided are an apparatus and method for managing data storage. A first log structured array stores data in a storage device. A second log structured array in the storage device stores metadata for the data in the first log structured array, wherein the second log structured array storing the metadata for the first log structured data storage system is nested within the first log structured array, and wherein the first and second log structured arrays comprise separate instances of log structured arrays. Address space is allocated in the second log structured array for metadata when the allocation of address space is required for metadata for data stored in the first log structured array.

Abstract: An apparatus for controlling a log-structured data storage system, operable with a first log-structured data storage area for storing data, comprises a metadata storage component for controlling the first log-structured data storage area and comprising a second log-structured data storage area for storing metadata; and means for nesting the second log-structured data storage area for storing metadata within the first log-structured data storage area. The apparatus may further comprise at least a third log-structured data storage area for storing further metadata, and means for nesting the at least a third log-structured data storage area within the second log-structured data storage area.

Abstract: A method is disclosed for reliably updating a data group in a read-before-write data replication environment. The method reliably updates the data group by receiving an updated data group sent from a first storage medium to a second storage medium, comparing the updated data group with a previous data group previously existing on the second storage medium and writing the updated data group to the second storage medium. The read-before-write and differencing method disclosed maintain reliability by storing multiple copies of changes made to the second storage medium during and after the write process.

Abstract: An apparatus for controlling a log-structured data storage system, operable with a first log-structured data storage area for storing data, comprises a metadata storage component for controlling the first log-structured data storage area and comprising a second log-structured data storage area for storing metadata; and means for nesting the second log-structured data storage area for storing metadata within the first log-structured data storage area. The apparatus may further comprise at least a third log-structured data storage area for storing further metadata, and means for nesting the at least a third log-structured data storage area within the second log-structured data storage area.

Abstract: An apparatus for controlling a log-structured data storage system, operable with a first log-structured data storage area for storing data, comprises a metadata storage component for controlling the first log-structured data storage area and comprising a second log-structured data storage area for storing metadata; and means for nesting the second log-structured data storage area for storing metadata within the first log-structured data storage area. The apparatus may further comprise at least a third log-structured data storage area for storing further metadata, and means for nesting the at least a third log-structured data storage area within the second log-structured data storage area.

Abstract: A system and method for solving the weak membership problem in a system of nodes that might include redundancies. Each node is given the same random seed. Each node uses a link state protocol to determine the current system topography, and then an optimization such as simulated annealing is run on the topography at each node, independently of the other nodes, to determine the optimum weak membership for use thereof in subsequent system operations. Since each node starts with the same random seed, the nodes all arrive at the same solution without having to communicate a common solution between nodes.

Abstract: A storage control system adapted to operate as a remote copy pair by communicating between a primary and a secondary of the remote copy pair comprises a selector for selecting writes to be placed in a batch based on one or more criteria, a sequence number requester for requesting a sequence number for the batch, and a sequence number granter for granting a sequence number for the batch. The storage control system also comprises a batch transmitter for transmitting the batch to the secondary, a permission receiver for receiving a permission to write the batch from the secondary, and a write component responsive to the permission receiver to write the batch to completion, wherein the secondary is responsive to the completion to grant a further permission to write for a further batch.

Abstract: A storage control system adapted to operate as a remote copy pair by communicating between a primary and a secondary of the remote copy pair comprises: a selector for selecting writes to be placed in a batch based on one or more criteria; a sequence number requester for requesting a sequence number for the batch; a sequence number granter for granting a sequence number for the batch; a batch transmitter for transmitting the batch to the secondary; a permission receiver for receiving a permission to write the batch from the secondary; and a write component responsive to the permission receiver to write the batch to completion; wherein the secondary is responsive to the completion to grant a further permission to write for a further batch.

Abstract: An apparatus configured to operate as a primary for a remote copy pair is provided. The apparatus comprises a journal component at said primary for generating journal entries for one or more uncompleted sequenced batches; a configurator responsive to an error indication from a secondary for enumeration of said one or more uncompleted sequenced batches; and a primary server responsive to said enumeration of said one or more uncompleted sequenced batches to reissue to said secondary one or more write requests for said one or more uncompleted sequenced batches, during recovery processing.

Abstract: Systems and methods are provided to implement fault tolerant data processing services based on active replication and, in particular, systems and methods for implementing actively replicated, fault tolerant database systems in which database servers and data storage servers are run as isolated processes co-located within the same replicated fault tolerant context to provide increased database performance.