Abstract: In one embodiment, an apparatus includes a storage presentation module and a mapping module in communication with the storage presentation module and an object pool module. The storage presentation module is operable to provide a first storage interface and a second storage interface via a network interface. The first storage interface is associated with a first storage resource accessible via a first storage protocol, and the second storage interface is associated with a second storage resource accessible via a second storage protocol different from the first storage protocol. The mapping module is operable to receive from the storage presentation module a request for access to the first storage resource based on the first storage protocol and a request for access to the second storage resource based on the second storage protocol.

Abstract: Transactions among kernel objects utilize application program interfaces (APIs) to implement operations on a transaction object and APIs to implement operations on a resource manager object.

Abstract: A storage system having a plurality of disks arranged in a RAID array with one of said disks being a replacement disk. A method and apparatus for restoring the contents of the replacement disk without interrupting concurrent access to the RAID array. An access request by a user application to a data block in the replacement disk results in regeneration and reconstruction of the accessed data block. In addition, the systematic reconstruction of data or parity blocks not yet accessed by the user application occurs by locating status bits associated with each data and parity block of the new disk.

Abstract: Data storage systems using a RAID-4 or RAID-5 organization divide an application I/O request into a number of individual I/O requests, each of which is contained within the boundaries of a single strip. The data blocks of each chunk on a strip responsive to an I/O request can form a complex geometric pattern requiring complicated operations to perform the I/O request. To simplify the necessary operations, each individual I/O request to a strip is divided into at most three requests targeted to data blocks forming a rectangle and each of these rectangles are processed as a unit. If a data block within a rectangle is unavailable, then the request to that rectangle is further subdivided into at most two requests targeted to data blocks forming smaller, non-overlapping rectangles which collectively are the original rectangle.

Abstract: A data storage system using a RAID array and a logging process and apparatus that identifies a parity block that may not contain the proper parity for its associated data blocks and which prevents such inconsistent parity information from being used in the regeneration of unavailable data. A small fraction of the blocks of each disk are dedicated to storing parity metadata bits. The parity metadata is associated with the parity blocks and identifies whether or not each parity block contains the proper parity information for its associated data blocks or may contain invalid information. The data integrity of the RAID array is preserved by preventing the generation of undetected corrupt data.