Abstract: Ordering data writes includes at least some of a group of local storage devices receiving a first plurality of data writes, waiting for all of the local storage devices to be ready to switch cycles and causing a coordinated and synchronized cycle switch after all of the local storage devices are ready to switch cycles by sending a first command to each of the local storage devices where the first plurality of data writes are associated with a particular cycle on each local storage device in the group. Ordering data writes also includes at least some of the group of local storage devices receiving a second plurality of writes after initiating the coordinated and synchronized cycle switch where all of the second plurality of writes are associated with a cycle different from the particular cycle on each local storage device.

Abstract: A computing system includes at least one source data center that generates data and a plurality of recovery groups, coupled to the at least one source data center, where each of the recovery groups includes a synchronous data center that receives synchronous data from the at least one source data center and includes an asynchronous data center that receives asynchronous data from the at least one source data center. Cycle switching for asynchronous data transfer is coordinated by the at least one source data center for a first subset of recovery groups containing at least two of the recovery groups. The computing system may also include a second subset of the recovery groups, different from the first subset, where cycle switching for asynchronous data transfer is coordinated by the at least one source data center for the second subset.

Abstract: Storing recovery data includes providing chunks of data to a remote destination, where each chunk of data represents data written before a first time and after a second time and where the second time for one of the particular chunks corresponds to a first time for a subsequent one of the particular chunks, providing synchronous data to a local destination, and providing an indicator to the local destination in connection with creation of a new chunk of data for storage at the remote destination. The local destination may maintain a plurality of maps, where each of the maps associates synchronous data being provided thereto with a specific chunk of data. In response to receiving an indicator in connection with creation of a new chunk of data, the local destination may point to a new map. There may be two maps or more than two maps.

Abstract: Handling failure of a primary group at a first data center that is part of plurality of data centers providing triangular asynchronous replication, includes creating a data mirroring relationship between at least one storage volume at a second data center having a synchronous backup group that is part of the plurality of data centers and at least one storage volume at a third data center having an asynchronous backup group that is part of the plurality of data centers and resuming work at the second data center. Handling failure of a primary group at a first data center may also include synchronizing the at least one storage volume at the second data center with the at least one storage volume at the third data center prior to resuming work at the second data center.

Abstract: A system for injecting I/O faults into a closed system, for example, the injection of link level I/O faults, involves the use of a simulated computing environment. In an embodiment, the system provides for fault injection using an emulated IBM System z environment and including the use of FICON and/or other suitable communication channel protocols. The emulated System z environment may include a simulated z/OS and/or emulated System z hardware and software components.

Abstract: Transferring storage device functionality includes providing a device coupled to the storage device, where the device is separate from the storage device, having the device handle I/O requests between an application and the storage device, and, in response to the application issuing an I/O request, having the device determine if the request corresponds to functionality being transferred and, if so, having the device provide the functionality. The device may be a host computer. The application may run on the host computer. A driver on the host computer may provide the functionality. The functionality may include read only functionality, data compression, data encryption, mirroring, and/or status reporting.

Abstract: A reclaim system provides for marking each track that is intended to be reclaimed in one or more storage devices and detecting and reclaiming such tracks. The reclaim system may include a feature and/or utility that may be used to mark, detect and return tracks to a free track pool of a virtual provisioning storage system in connection with the use of one or more thin Count Key Data (CKD) devices. Reclaim processing may include identifying tracks to be reclaimed, marking mark the tracks to be reclaimed, detecting tracks that have been marked to be reclaimed, and performing a reclaim task to return the marked and detected tracks to the free track pool, thereby reclaiming the tracks.

Abstract: Handling failure of a primary group at a first data center that is part of plurality of data centers providing triangular asynchronous replication, includes creating a data mirroring relationship between at least one storage volume at a second data center having a synchronous backup group that is part of the plurality of data centers and at least one storage volume at a third data center having an asynchronous backup group that is part of the plurality of data centers and resuming work at the second data center. Handling failure of a primary group at a first data center may also include synchronizing the at least one storage volume at the second data center with the at least one storage volume at the third data center prior to resuming work at the second data center.

Abstract: Maintaining tape emulation consistency includes writing additional tape data to a first local storage device at a local site, writing tape emulation data to a second local storage device at the local site, where the second local storage device is different from the first local storage device, and maintaining consistency of the first and second local storage devices in connection with transferring data to a remote site. Maintaining consistency of the first and second local storage devices may include initiating a cycle switch that causes a concurrent cycle change from a first cycle to a second cycle for the first and second local storage devices. Additional tape data and tape emulation data written before a first time is associated with a first cycle. Additional tape data and tape emulation data written after the first time and before a second time is associated with a second cycle.

Abstract: A computer-implemented method of ordering data writes includes at least some of a plurality of primary storage devices receiving a first plurality of data writes and causing a cycle switch for the plurality of primary storage devices. The first plurality of data writes are associated with a particular cycle on each primary storage device in the plurality of primary storage devices. At least some of the plurality of primary storage devices receive a second plurality of writes after initiating the cycle switch. All of the second plurality of writes are associated with a cycle different from the particular cycle on each of the plurality of primary storage devices.

Abstract: Described are techniques for providing access to storage devices. An I/O request directed to a storage device is sent over a network connection from a first computer system to a second computer system. The second computer system includes a simulated computing environment simulating aspects of the first computer system. The I/O request is received at the second computer system. The data storage system is connected to the second computer system over a first connection operating in accordance with a first protocol thereby providing the second computer system access to the storage device of the data storage system. The simulated computing environment of the second computer system may, for example, include emulation capabilities in accordance with the first protocol thereby allowing the second computer system to issue the first I/O request to the first storage device on behalf of the first computer system.

Abstract: A computing system includes at least one source data center that generates data and a plurality of recovery groups, coupled to the at least one source data center, where each of the recovery groups includes a synchronous data center that receives synchronous data from the at least one source data center and includes an asynchronous data center that receives asynchronous data from the at least one source data center. Cycle switching for asynchronous data transfer is coordinated by the at least one source data center for a first subset of recovery groups containing at least two of the recovery groups. The computing system may also include a second subset of the recovery groups, different from the first subset, where cycle switching for asynchronous data transfer is coordinated by the at least one source data center for the second subset.

Abstract: Handling failure of a primary group at a first data center that is part of plurality of data centers providing triangular asynchronous replication, includes creating a data mirroring relationship between at least one storage volume at a second data center having a synchronous backup group that is part of the plurality of data centers and at least one storage volume at a third data center having an asynchronous backup group that is part of the plurality of data centers and resuming work at the second data center. Handling failure of a primary group at a first data center may also include synchronizing the at least one storage volume at the second data center with the at least one storage volume at the third data center prior to resuming work at the second data center.

Abstract: Transferring storage device functionality includes providing a device coupled to the storage device, where the device is separate from the storage device, having the device handle I/O requests between an application and the storage device, and, in response to the application issuing an I/O request, having the device determine if the request corresponds to functionality being transferred and, if so, having the device provide the functionality. The device may be a host computer. The application may run on the host computer. A driver on the host computer may provide the functionality. The functionality may include read only functionality, data compression, data encryption, mirroring, and/or status reporting.

Abstract: Maintaining continuous availability of tape data includes providing a first storage space that contains the tape data, where metadata for the tape data points to the first storage space, creating a data mirroring relationship between the first storage space and a second, separate, storage space, where tape data written to the first storage space is copied to the second storage space, and adjusting the metadata for the tape data to reference the second storage space in response to the first storage space becoming inaccessible. Maintaining continuous availability of tape data may also include suspending access to the tape data prior to adjusting the metadata. Maintaining continuous availability of tape data may also include resuming access to the tape data after adjusting the metadata.

Abstract: Maintaining tape emulation consistency includes writing additional tape data to a first local storage device at a local site, writing tape emulation data to a second local storage device at the local site, where the second local storage device is different from the first local storage device, and maintaining consistency of the first and second local storage devices in connection with transferring data to a remote site. Maintaining consistency of the first and second local storage devices may include initiating a cycle switch that causes a concurrent cycle change from a first cycle to a second cycle for the first and second local storage devices. Additional tape data and tape emulation data written before a first time is associated with a first cycle. Additional tape data and tape emulation data written after the first time and before a second time is associated with a second cycle.

Abstract: Described are techniques used in defining and maintaining group data used by multiple host systems. Group data is stored in a distributed fashion on one or more data storage systems. If a device of a data storage system belongs to a group, group data for that group is stored on that data storage system. Group data changes made by one host are communicated to the other hosts by accessing a common data area on each data storage system using a daemon executing on each host. Remotely mirrored groups may be defined on a remote data storage system. A remote mirror of a group includes group data modified in accordance with a point of view of the remote data storage system and a remote host.

Abstract: Handling a database request includes providing a first database manager on a storage device containing data for the database, generating the database request external to the storage device, providing the database request to the first database manager on the storage device, and the first database manager servicing the database request by obtaining data internally from the storage device and processing the data within the storage device to provide a result thereof, wherein portions of the data that are not part of the result are not provided externally from the storage device. Handling a database request may also include providing a host having a database application running thereon. The database request may be generated by the database application. Handling a database request may also include providing a second database manager on the host, where the second database manager communicates with the first database manager to provide the database request.

Abstract: Managing data on a storage device includes intercepting unencrypted data to be stored on the storage device, where intercepting unencrypted data is transparent to an application storing the data on the storage device and encrypting the data prior to storage on the storage device. The storage device may include a tape drive and/or a disk drive. Managing data on a storage device may also include migrating data from a first storage location to a second storage location. The first storage location may be the same as the second storage location or the first storage location may be different from the second storage location. The unencrypted data may be intercepted during migration. Managing data on a storage device may also include decrypting data read from the storage device.

Abstract: Storing recovery data includes a host processor writing data to a local storage device, the host processor causing the local storage device to accumulate chunks of data corresponding to writes by the host processor, where each chunk of data represents data written before a first time and after a second time and where the second time for one of the particular chunks of data corresponds to a first time for a subsequent one of the particular chunks of data, transmitting the chunks of data from the local storage device to a remote destination, providing synchronous data from the local storage device to a local destination; and, the host processor causing an indicator to be provided to the local destination in connection with creation of a new chunk of data for storage at the remote destination. The local destination may maintain a plurality of maps, where each of the maps associates synchronous data being provided thereto with a specific chunk of data.