Abstract: Generating a consistent point in time copy of data in a source volume and a target volume is achieved responsively to a first data modification request by writing a first altered version of the data onto a single source volume, asynchronously transferring the first altered version from the first storage site to a target volume located at a remote second storage site, while avoiding copying the first altered version onto other volumes at the first storage site. While asynchronously transferring the first altered version de-queuing a second modification request, and responsively to the second modification request synchronously transferring the first altered version from the first storage site to the target volume. Then a second altered version of the data is written to the single source volume and a copy transferred to the target volume in like manner.

Abstract: Provided are a method, system, and article of manufacture, wherein a primary control unit sends a selected time to a plurality of secondary control units. Clocks are periodically synchronized at the primary control unit and the secondary control units with a time server. The primary control unit and the plurality of secondary control units consistently update secondary storage subsystems coupled to the plurality of secondary control units at the selected time.

Abstract: Provided are a method, system, and program for maintaining consistency when mirroring data using different copy technologies. Update groups having updates to primary storage locations are formed using a first copy technology. The updates in the update groups are copied to secondary storage locations. Update groups having updates to primary storage locations are formed using a second copy technology, wherein the updates in the update groups are copied to secondary storage locations. Indication is made in a data structure of a time of an update in response to including the update in one of the update groups formed using the first copy technology. Indication is also made in the data structure of a time of the update group formed using the second copy technology.

Abstract: An enhanced mechanism for the allocation, organization and utilization of high performance block storage metadata provides a stream of data (e.g., in a server system, storage system, DASD, etc.) that includes a sequence of fixed-size blocks which together define a page. Each of the fixed-size blocks includes a data block and a footer. A high performance block storage metadata unit associated with the page is created from a confluence of the footers. Each footer in the confluence of footers has space available for application metadata, which are provided as one or more information units. At least one of the footers includes a Checksum field containing a checksum that covers at least the confluence of footers. This approach is advantageous in that it provides data integrity protection, protects against stale data, and significantly increases the amount of metadata space available for application use.

Abstract: Providing extended or end-to-end data integrity through layers of a system. In one aspect, information is to be transmitted between an application end of the system and a physical storage medium that stores the information for a database of the system, the information to be transmitted via a database server in a database server layer of the system. At least a portion of data protection is provided for the information, the data protection causing the information to be protected from corruption between a system layer and the physical storage medium, where the system layer is a separate layer provided closer to the application end of the system than the database server layer.

Abstract: A method for managing operations in a data storage system comprising at least a first storage controller operating according to a plurality of operation states set by a managing entity is provided. The method comprises the first storage controller performing a first operation associated with a first operation state, in response to the managing entity updating state information stored in a data structure readable by the first storage controller.

Abstract: Provided are a method, system, and article of manufacture for a replication engine communicating with a splitter to split writes between a storage controller and replication engine. Communication is initiated with the splitter implemented in a storage controller managing access to primary volumes. A command is sent to the splitter to copy writes to one primary volume to the replication engine. Write data is received from the splitter to one of the primary volumes following the splitter receiving the command to copy the writes to the replication engine. A determination is made of a copy services function to use for the received data. The determined copy services function is invoked to transfer the received data to a secondary storage volume.

Abstract: Provided are a method, system, and article of manufacture for splitting writes between a storage controller and replication engine. A splitter executing in a storage controller manages access to primary volumes. An initialization command is received to communicate with a replication engine. A replication command is received for one primary volume and the primary volume is indicated as subject to replication. A write request is received to write data to a target primary volume of the primary volumes that is indicated as subject to the replication. The data in the write request is written to the target primary volume. The data in the write request is sent to the replication engine. The replication engine executes a copy services function associated with the target primary volume to write the data to a replication engine volume.

Abstract: Provided are a method, system, and article of manufacture for copying writes from primary storages to secondary storages across different networks. A failure notification is communicated, using a first network protocol, from a primary device in a first group of at least one primary device and at least one corresponding primary storage managed by the at least one primary device to a control system in response to the primary device determining that a write to the primary storage cannot be copied to a corresponding secondary storage. A failure notification is communicated, using a second network protocol, from a primary device in a second group of at least one primary device and at least one corresponding primary storage managed by the at least one primary device to the control system in response to the primary device determining that a write to the corresponding primary storage cannot be copied to a corresponding secondary storage.

Abstract: Provided are a method, system, and article of manufacture for managing the copying of writes from primary storages to secondary storages across different networks. Information is maintained on a first group of at least one primary storage, at least one primary device managing Input/Output (I/O) access to the at least one primary storage, and at least one corresponding secondary storage to which writes to the at least one primary storage are copied and a second group of at least one primary storage, at least one primary device managing Input/Output (I/O) access to the at least one primary storage, and at least one corresponding secondary storage to which writes to the at least one primary storage are copied. A failure notification is received from one of the primary devices in the first or second group of a failure to copy a write from the primary device to the secondary device.

Abstract: A network component useful in tracking write activity by writing logs containing write address information is described. The tracking component may be used in networked systems employing data mirrors to record data block addresses written to a primary storage volume during the time a data mirror is unavailable. The tracking component can be available to any network originating node, and may therefore track write activity on multiple volumes. At the time a data mirror is reconstructed, the log written may be used to construct a list of block addresses pointing to locations on a primary storage volume wherein data differs from a secondary storage volume member of the mirror. The locations may be copied from the primary to secondary storage volume to reconstruct the data mirror. The performance impact of the tracking component is minimal and a shared network resource is offered that increases fault tolerance in the event of backup device failures.

Abstract: A data storage system writes data supplied from a host to data storage in accordance with write I/O of an owning application. A workload manager directs the processing of the supplied data in accordance with the write I/O of the owning application, provides service workload identification describing the write I/O, a storage subsystem control adds the service workload identification to record set information for the data, and a journal management system stores the record set information in a journal. The journaled information, for example, may be employed for performing forensic analysis of data corruption events or to perform security audits, etc.

Abstract: A data storage system writes data supplied from a host to data storage in accordance with write I/O of an owning application. A workload manager directs the processing of the supplied data in accordance with the write I/O of the owning application, provides service workload identification describing the write I/O, a storage subsystem control adds the service workload identification to record set information for the data, and a journal management system stores the record set information in a journal. The journaled information, for example, may be employed for performing forensic analysis of data corruption events or to perform security audits, etc.

Abstract: A network component useful in tracking write activity by writing logs containing write address information is described. The tracking component may be used in networked systems employing data mirrors to record data block addresses written to a primary storage volume during the time a data mirror is unavailable. The tracking component can be available to any network originating node, and may therefore track write activity on multiple volumes. At the time a data mirror is reconstructed, the log written may be used to construct a list of block addresses pointing to locations on a primary storage volume wherein data differs from a secondary storage volume member of the mirror. The locations maybe copied from the primary to secondary storage volume to reconstruct the data mirror. The performance impact of the tracking component is minimal and a shared network resource is offered that increases fault tolerance in the event of backup device failures.

Abstract: Disclosed are a system, a method, and a computer program product to provide for the optimization of the output transfer load balance between the peer computers transferring data to one or more storage devices. The peer computers receive, organize and transfer the data to storage devices. The data set is composed of a plurality of data transfers. After an initial division of the data transfers between the two peers, each peer will have assigned responsibility for a number of data transfers. If the one of the peer computers completes offloading transactions earlier than the other peer, then the peer that is still transferring data will employ the other peer to execute a portion of the remaining data transfers. The operation of the system is symmetrical in that either peer may assist the other peer depending upon which peer has idle time.

Abstract: Provided are a method, system and article of manufacture for switching. An indication is received of a failure of a primary storage subsystem at a switch, wherein the switch couples a host to the primary storage subsystem and a secondary storage subsystem. Subsequently, a command received from the host at the switch is directed to the secondary storage subsystem for completion.

Abstract: Disclosed are a system, a method, and a computer program product to provide for the optimization of the output transfer load balance between the peer computers transferring data to one or more storage devices. The peer computers receive, organize and transfer the data to storage devices. The data set is composed of a plurality of data transfers. After an initial division of the data transfers between the two peers, each peer will have assigned responsibility for a number of data transfers. If the one of the peer computers completes offloading transactions earlier than the other peer, then the peer that is still transferring data will employ the other peer to execute a portion of the remaining data transfers. The operation of the system is symmetrical in that either peer may assist the other peer depending upon which peer has idle time.

Abstract: Provided are a method, system, and article of manufacture, wherein a controller receives a request from one of a plurality of hosts. The controller determines whether a primary storage control unit coupled to the controller is operational. A response is generated by accessing the primary storage control unit, in response to determining that the primary storage control unit is operational. The response is generated by accessing a secondary storage control unit, in response to determining that the primary storage control unit is not operational, wherein data is replicated synchronously from the primary storage control unit to the secondary storage control unit.

Abstract: A method for generating a consistent point in time copy of data, the method includes: selecting at least one selected data block to be copied from a source volume to a target volume in response to a request to generate a consistent point in time copy of multiple data blocks; waiting until the source volume is ready to send the at least one selected data block to a remote volume while queuing at least one data block modify request; de-queuing the at least one queued modify requests while copying the at least one selected data block from the source volume to the target volume; wherein the copying includes utilizing a first copying mechanism to copy a first selected data block if a request to modify the first selected block is de-queued before the first selected data block is copied to the target volume; else, the copying includes using a second copying mechanism that is slower than the first copying mechanism.

Abstract: Provided are a method, system, and article of manufacture for mirroring data between a first site and a second site. Updates to segments of storage at the first site are copied to corresponding segments of storage at the second site. Codes are generated from the segments at the second site and a valid flag is provided for at least one code indicating whether the code for the segment of data is valid. One code is generated from each segment of storage at the first site. An operation is initiated to copy segments from the second site to the first site. A determination is made for segments at the second site as to whether the valid flag for the code for the segment at the second site indicates that the code is valid in response to initiating the copy operation. The valid code for at least one segment in the second site is compared with the code for the corresponding segment at the first site to determine whether to copy the data from the segment at the second site to the first site as part of the copy operation.