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: 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: 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 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: 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: 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.

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: 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: Storing recovery data for a data center includes providing synchronous data from the data center to a local destination, providing chunks of data from the local destination to a first remote destination, different from the first remote destination, and providing chunks of data from the data center to a second remote destination. At least some of the destinations may maintain a plurality of maps, where each of the maps associates synchronous data being provided to the local destination with a specific chunk of data. In response to receiving an indicator in connection with creation of a new chunk of data, the at least some of the destinations that maintain a plurality of maps may point to a new map. There may be two maps or more than two maps.

Abstract: Toggling between a first storage configuration and a second storage configuration includes disabling asynchronous data transfer to a third storage group from one of the first storage group and the second storage group and enabling asynchronous data transfer to the third storage group from an other one of the first storage group and second storage group. Toggling between a first storage configuration and a second storage configuration may also include, prior to disabling asynchronous data transfer to the third storage group, transferring pending data to the third storage group. Toggling between a first storage configuration and a second storage configuration may also include, after enabling asynchronous data transfer to the third storage group, transferring data to the third storage group that had been pending prior to disabling asynchronous data transfer to the third storage group.

Abstract: Providing storage configurations for a data center includes providing synchronous data transfer from the data center to a local destination, establishing a first connection between the data center and a remote destination to provide chunks of data from the data center to a remote destination, establishing a second connection between the local destination and the remote destination to provide chunks of data from the local destination to the remote destination, and enabling at least one of the first and second connections to transfer chunks of data to the remote destination.

Abstract: Handling failure of a primary group at a first data center may be simulated by cloning the at least one storage volume at a second data center, cloning at least one storage volume at a third data center, cloning at least one of: buffers used for providing data to the asynchronous backup group and maps used to maintain a record of data sent to the synchronous backup group but not yet sent to the asynchronous backup group; and simulating resuming work at one of the second data center and the third data center using at least one of clones of the buffers and clones of the maps.

Abstract: Described are techniques used in performing data replication processing. Data is replicated on a recovery site from a production site. When a disaster occurs, the state of the replication processing is determined and a restart copy of the data is made available from the recover site. Processing continues based on whether protection mode is desired such that the system executes using the recovery site as the restart with a replicated copy of the data. Data is propagated from the recovery site to the production site to resume operations and replication processing originating from the production site.

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 third 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 third data center.

Abstract: Described are techniques used in performing data replication processing. Data is replicated on a recovery site from a production site. When a disaster occurs, the state of the replication processing is determined and a restart copy of the data is made available from the recover site. Processing continues based on whether protection mode is desired such that the system executes using the recovery site as the restart with a replicated copy of the data. Data is propagated from the recovery site to the production site to resume operations and replication processing originating from the production site.