Abstract: The present invention combines IP multicasting mechanisms with SCSI protocols to achieve a more efficient data replication or data mirroring scheme. The combination of the IP multicast mechanism with the mapping of virtual unit logical number to real logical unit numbers, combined with the use of SCSI response frames, ensures the integrity of multicasted data. By use of the SCSI protocol over the TCP/IP according to the present invention, there is no further need to transfer multiple copies of the same data on the same communication link, and the routing logic may be removed from initiator and targets to IP routers.

Abstract: A system and method is described for use in the propagation of cross-platform updates of databases in, for example, an Enterprise system. Given that these platforms may be operating using different operating systems and database software, the system and method are not application dependent. The system and method effect the cross-platform propagation of updates through the use of I/O streams. Accordingly, the system and method do not use valuable and expensive CPU cycles nor excessively load the TCP/IP communication lines to perform the desired cross-platform propagation of updates for platform databases.

Abstract: Systems and methods of servicing requests of a first file system communicated in accordance with a first storage protocol using a storage system that is responsive to requests communicated according to a second storage protocol and that is organized in accordance with a second file system. Among other things, this allows the use of potentially more reliable and robust storage systems for holding information of the first file system and allows potentially more reliable and robust management tools to manage the information of the first file system.

Abstract: The disclosed device, system and methods of data management facilitate the implementation of improved mirroring, back-up, volume remapping and extent relocation, among others. The disclosed intelligent I/O stream splitter may intercept and alter an I/O stream from a communications link. In the case of mirroring, the intelligent splitter may intercept write commands and associated data from a mainframe that target a specific storage location on a specific control unit. The splitter may then transmit the intercepted I/O stream to the targeted control unit and storage location over one link and transmit on another link an altered version of the intercepted I/O stream to another control unit, which is responsible for holding a mirrored version of the data. The altered version could have the same data as that on the one link, or may include new frame headers, changes to the control information, or changes to the data itself.

Abstract: A device, system and methods of data management are disclosed, which facilitate the implementation of improved mirroring, back-up, volume remapping, extent relocation, prefetching, caching, data reformatting, statistic gathering, and data translation, among others. A new, intelligent I/O stream splitter is disclosed that may intercept and alter an I/O stream received by the splitter from a communications link. For example, in the case of mirroring, the intelligent splitter may intercept write commands and associated data from a mainframe that target a specific storage location on a specific control unit. The splitter may then transmit the intercepted I/O stream to the targeted control unit and storage location over one link and in parallel transmit on another link an altered version of the intercepted I/O stream to another control unit, which is responsible for holding a mirrored version of the data.

Abstract: A method of creating a snapshot copy of data stored on a first direct access storage device is described. It includes the acts of receiving information identifying a set of data that is to be copied from the first direct access storage device and mapping destination locations in a second direct access storage device for each element of the set. The destination locations are in a sequence emulating a tape copy. The method also includes the acts of iterating through the set of data. For the each element of the set, the method of the present invention also includes the acts of determining if the element has already been copied to the second direct access storage device, and, if the element has not already been copied, then copying the element to its mapped location in the second direct access storage device. A corresponding system is also described.

Abstract: A method of creating a snapshot copy of data stored on a first direct access storage device is described. It includes the acts of receiving information identifying a set of data that is to be copied from the first direct access storage device and mapping destination locations in a second direct access storage device for each element of the set. The destination locations are in a sequence emulating a tape copy. The method also includes the acts of iterating through the set of data. For the each element of the set, the method of the present invention also includes the acts of determining if the element has already been copied to the second direct access storage device, and, if the element has not already been copied, then copying the element to its mapped location in the second direct access storage device. A corresponding system is also described.

Abstract: Systems and methods of servicing requests of a first file system communicated in accordance with a first storage protocol using a storage system that is responsive to requests communicated according to a second storage protocol and that is organized in accordance with a second file system. Among other things, this allows the use of potentially more reliable and robust storage systems for holding information of the first file system and allows potentially more reliable and robust management tools to manage the information of the first file system.

Abstract: A system and method is described for use in the propagation of cross-platform updates of databases in, for example, an Enterprise system. Given that these platforms may be operating using different operating systems and database software, the system and method are not application dependent. The system and method effect the cross-platform propagation of updates through the use of I/O streams. Accordingly, the system and method do not use valuable and expensive CPU cycles nor excessively load the TCP/IP communication lines to perform the desired cross-platform propagation of updates for platform databases.

Abstract: The present invention combines IP multicasting mechanisms with SCSI protocols to achieve a more efficient data replication or data mirroring scheme. The combination of the IP multicast mechanism with the mapping of virtual unit logical number to real logical unit numbers, combined with the use of SCSI response frames, ensures the integrity of multicasted data. By use of the SCSI protocol over the TCP/IP according to the present invention, there is no further need to transfer multiple copies of the same data on the same communication link, and the routing logic may be removed from initiator and targets to IP routers.

Abstract: A method and apparatus for improving storage controller throughput when servicing non-specific read requests. Throughput is increased by enabling the storage controller to service non-specific read requests issued against a device address which is not the same as the device address associated with the data that the non-specific read is requesting. The device address associated with the data is thus free to be used for another I/O operation. When the device address used by the non-specific read is a non-busy type (that is, the device and/or data is not locked) then the throughput improvement is obtained by increasing the number of data requests that may be concurrently handled by the storage controller.

Abstract: A data backup copying session on a data processing system is secured responsive to initiation of the data backup session by an application executing on a processing unit by generating a unique identifier for the data backup session. Thereafter, all member paths of a group of paths designated by the processing unit for communication between itself and the first storage subsystem are identified and associated with the data backup session. Access to the session is thereafter allowed only along a member path of the group of paths associated with the data backup session. The system and method of the invention further provide for fault recovery and protection against excessive demand on storage control unit memory.

Abstract: A method and system for efficiently accessing desired datasets among multiple datasets which are stored at specific data addresses within multiple storage subsystems which are coupled to a host system via a storage subsystem controller and a data channel. A data request is transmitted from the host system to the storage subsystems via the data channel. The data request specifies non-address attributes for desired datasets, such as boundary addresses for large data extents including many datasets or a request for all datasets modified since the occurrence of a specified event. The data request is then processed at the storage subsystem controller to determine a data address for each dataset within the storage subsystem which possess the desired attributes. Thereafter, the desired datasets are transmitted via the data channel to the host system in association with a specific address for each dataset.

Abstract: A method and system are disclosed for permitting high concurrency of access during backup copying of designated data stored within a storage subsystem which includes multiple storage devices coupled to the data processing system via a storage subsystem control unit having subsystem memory therein. Data within each storage device is accessed utilizing a Unique Control Block (UCB), which identifies a selected storage device, and an associated data retrieval command sequence which identifies the data to be accessed. Portions of the data copied to subsystem memory within the subsystem storage control unit as sidefiles from a first storage device may be accessed utilizing a Unique Control Block (UCB) associated with an alternate storage device by associating a selected data retrieval command sequence therewith which identifies the data as stored within the subsystem memory.

Abstract: A method and system are disclosed for enhanced efficiency of backup copying of designated datasets stored within a plurality of storage devices coupled to the data processing system via a storage subsystem control unit having subsystem memory therein. Application execution within the data processing system is temporarily suspended long enough to form a dataset logical-to-physical system address concordance to be utilized to administer copying of the designated dataset. Thereafter, application initiated updates to uncopied portions of the designated datasets are temporarily deferred until sidefiles of the affected portions of the designated datasets are written to subsystem memory. The updates are then written to the storage subsystem. Portions of the designated datasets are then accessed and copied from the storage subsystem on a scheduled or opportunistic basis utilizing selected data retrieval command sequences.