Abstract: A data storage system is provided comprising memory allocation information associated with a change in a system configuration of memory allocation within a memory space, and means for updating the system configuration by saving the memory allocation information before updating the system configuration. A recovery record comprises memory allocation information associated with the change in system configuration of memory allocation, and a completion indicator comprises a first value if the memory allocation information is included in the system configuration and comprises a second value if the memory allocation information is not included in the system configuration.

Abstract: Method and apparatus for adaptive arrangement of data on storage media, such as in a multi-device storage array across which data are stored. A virtual hot space is formed to store frequently accessed data. The virtual hot space comprises at least one hot data zone which extends across storage media of a plurality of arrayed storage devices over a selected seek range less than an overall radial width of the media. The frequently accessed data are stored to the hot data zone(s) in response to a host level request, such as from a host level operating system (OS) or by a user which identifies the data as frequently accessed data. Alternatively or additionally, access statistics are accumulated and frequently accessed data are migrated to the hot data zone(s) in relation thereto. Lower accessed data sets are further preferably migrated from the hot data zone(s) to another location of the media.

Abstract: A storage system permits virtual storage of user data by implementing a logical disk mapping structure that provides access to user data stored on physical storage media and methods for generating point-in-time copies, or snapshots, of logical disks. A snapshot logical disk is referred to as a predecessor logical disk and the original logical disk is referred to as a successor logical disk. Creating a snapshot involves creating predecessor logical disk mapping data structures and populating the data structures with metadata that maps the predecessor logical disk to the user data stored on physical media. Logical disks include metadata that indicates whether user information is shared between logical disks. Multiple generations of snapshots may be created, and user data may be shared between these generations. Methods are disclosed for maintaining data accuracy when write I/O operations are directed to a logical disk.

Abstract: Disclosed is a data storage architecture employing a plurality of data grids each comprising an array of equal capacity data storage blocks organized into a plurality of rows and a plurality of columns such that each column corresponds to a storage domain in a data storage system and each row of the plurality of rows corresponds to a plurality of data storage blocks, one data storage block from each column of the plurality of columns at the same physical address, with the plurality of rows each having a plurality of contiguous data storage blocks in each domain. Capacity grids are produce by applying one of a plurality of sparing versions that designate at least one data storage block in each row of the grid is designated as spare, Defined within each capacity grid are one or more data storage units.

Abstract: A system and method for high performance multi-controller processing is disclosed. Independent Network storage controllers (NSCs) are connected by a high-speed data link. The NSCs control a plurality of storage devices connected by a Fiber Channel Arbitrated Loop (FCAL). To provide redundancy, for a given logical unit of storage one NSC will function as the primary controller and the other NSC will function as a mirror controller. To enhance the efficiency of command-response data transfers between NSCs, mirror memory is correlated with primary memory and named resources are used for command-response data transfers. Methods are disclosed to provide for efficient active mirroring of data.

Abstract: A storage system permits virtual storage of user data by implementing a logical disk mapping structure that provides access to user data stored on physical storage media and methods for generating point-in-time copies, or snapshots, of logical disks. A snapshot logical disk is referred to as a predecessor logical disk and the original logical disk is referred to as a successor logical disk. Creating a snapshot involves creating predecessor logical disk mapping data structures and populating the data structures with metadata that maps the predecessor logical disk to the user data stored on physical media. Logical disks include metadata that indicates whether user information is shared between logical disks. Multiple generations of snapshots may be created, and user data may be shared between these generations. Methods are disclosed for maintaining data accuracy when write I/O operations are directed to a logical disk.

Abstract: Systems, methods and software for implementing a virtualized storage system. Physical storage is carved into units called physical segments. Logical storage is implemented in atomic logical units called RStores comprising a range of virtual address space that when allocated, is bound to a particular group of PSEGs. RStores preferably implement a selected level of data protection. A pool of physical storage devices is carved into redundant storage sets. A plurality of RStores make up a logical disk that is presented to a user. Storage access requests expressed in terms of logical disk addresses are mapped to PSEGs containing data represented by the logical addresses through a split-directory representation of the logical unit.

Abstract: Systems, methods and software for implementing a virtualized storage system. Physical storage is carved into units called physical segments. Logical storage is implemented in atomic logical units called RStores comprising a range of virtual address space that when allocated, is bound to a particular group of PSEGs. RStores preferably implement a selected level of data protection. A pool of physical storage devices is carved into redundant storage sets. A plurality of RStores make up a logical disk that is presented to a user. Storage access requests expressed in terms of logical disk addresses are mapped to PSEGs containing data represented by the logical addresses through a split-directory representation of the logical unit.

Abstract: A system and method for high performance multi-controller processing is disclosed. Independent Network storage controllers (NSCs) are connected by a high-speed data link. The NSCs control a plurality of storage devices connected by a Fiber Channel Arbitrated Loop (FCAL). To provide redundancy, for a given logical unit of storage one NSC will function as the primary controller and the other NSC will function as a mirror controller. To enhance the efficiency of command-response data transfers between NSCs, mirror memory is correlated with primary memory and named resources are used for command-response data transfers. Methods are disclosed to provide for efficient active mirroring of data.

Abstract: A management interface for a virtualized storage system including a virtualized logical disk object representing a virtual storage container, wherein the logical disk is an abstract representation of physical storage capacity provided by plurality of physical stores. A virtual disk object represents a virtual storage container. The virtual disk object is an abstract representation of one or more logical disk objects, the virtual disk object including an exposed management interface. Wherein the virtual disk object is managed through the management interface to select the one or more logical disk objects represented by the virtual disk object.

Abstract: A storage system permits virtual storage of user data by implementing a logical disk mapping structure that provides access to user data stored on physical storage media and methods for generating point-in-time copies, or snapshots, of logical disks. A snapshot logical disk is referred to as a predecessor logical disk and the original logical disk is referred to as a successor logical disk. Creating a snapshot involves creating predecessor logical disk mapping data structures and populating the data structures with metadata that maps the predecessor logical disk to the user data stored on physical media. Logical disks include metadata that indicates whether user information is shared between logical disks. Multiple generations of snapshots may be created, and user data may be shared between these generations. Methods are disclosed for maintaining data accuracy when write I/O operations are directed to a logical disk.

Abstract: Provided herein is a method and apparatus for host transparent storage controller failover and failback. A controller is capable of assuming the identity of a failed controller while continuing to respond to its own SCSI ID or IDs in such a way that all SCSI IDs and associated units (LUNS) of the failed controller are effectively taken over by the surviving controller. This "failover" behavior is transparent to any attached host computers and is treated by such attached hosts as a powerfail condition. The symmetric operation of returning the targets (IDs) and units (LUNs) to the previously failing controller ("failback") is likewise transparent.