Abstract: Migrating data from a first storage system to a second storage system includes transferring the data from the first storage system to a cloud storage, transferring the data from the cloud storage to the second storage system, quiescing the first storage system prior to transferring remaining data from the first storage system to the cloud storage, and transferring remaining data from the cloud storage to the second storage system to complete migration of the data. The cloud storage may be accessible only through a private network or via the World Wide Web. Quiescing the first storage system may include the first storage system rejecting write operations or may include one or more external systems coupled to the first storage system foregoing write operations. Snapshots may be performed at the first storage system in response to commands provided by a host coupled to the first storage system.

Abstract: Adapting a storage system in response to operation of a corresponding host includes determining whether the host is performing a boot up operation, determining whether the host is performing a shutdown operation, and adapting operation of the storage system in response to the host performing one of: a boot up operation or a shutdown operation. Adapting operation of the storage system may include suspending low-priority housekeeping tasks, decreasing work queue scan times to be more responsive to incoming work, moving cores from other emulations, increasing thread counts, and/or preloading specified files into cache memory of the storage system. Determining whether the host is performing a boot up operation may include making a call from the storage system to the host that causes the host to return an indication thereof. Operations that are characteristic of booting up may be determined by machine learning.

Abstract: Causing data in an in-band storage device coupled to a host computing system to be transferred to an out-of-band (OOB) storage device includes coupling the in-band storage device to the OOB storage device, the in-band storage device detecting commands from the host computing system to transfer the data in the in-band storage device to a cloud storage, and the in-band storage device transferring the data in the in-band storage device to the to the OOB storage device in response to receiving a command from the host computing system to transfer the data in the in-band storage device to the cloud storage. The OOB storage device may be coupled to the cloud storage. Causing data in an in-band storage device to be transferred to an OOB storage device may also include causing data stored at the OOB storage device to be transferred to the cloud storage.

Abstract: Writing new data to a tape volume of a tape emulation unit includes determining if the new data is an update to data that was previously written, writing the new data to a new section of the tape emulation unit in response to the new data not updating data that was previously written, deleting the data that was previously written and writing the new data to a new section in response to the new data updating data that was previously written, the new data being larger than the data that was previously written, and the underlying file system not supporting variable size records/blocks, and overwriting the data that was previously written in response to the new data updating data that was previously written and either the new data not being larger than the data that was previously written or the underlying file system supporting variable size records/blocks.

Abstract: Transferring data from a storage device to cloud service includes initiating a snapshot of the data, accessing each block of the data corresponding to the snapshot to transfer each block to the cloud service, and terminating the snapshot after all of the blocks have been transferred to the cloud service. At least some blocks of the storage device that are modified after initiating the snapshot may be copied from the storage device to a storage pool prior to modification. Only a first modification of a particular one of the blocks of the storage device may cause the particular one of the blocks to be copied to the storage pool. Accessing each block of the data may include accessing blocks of the storage pool. Modifying a particular one of the blocks of the storage device may include modifying a corresponding block of a storage pool.

Abstract: Replicating data written to a local storage device from a host includes receiving the incoming data using a first director that mirrors the incoming data from the first director to a second director independently of any links that transmit data to or from the directors and other components of the local storage device and transmitting the mirrored data from the local storage device to a remote storage device. The first director may be a target device (e.g., FICON target) that accepts data and connection requests from the host. The second director may be an initiator device (e.g., FICON initiator) that provides data and connection requests to the remote storage device. The second director may emulate a FICON initiator. The local storage device may wait for an acknowledgement of receipt of the data from the remote storage device before acknowledging receipt to the host.

Abstract: Migrating data from a first storage device to a second storage device includes causing all data of the first storage device to be copied from the first storage device to the second storage device and causing the host computer to transition from performing I/O operations with the first storage device to performing I/O operations with the second storage device by modifying metadata used for I/O operations to change a mapping of logical devices to physical devices only after causing all data of the first storage device to be copied from the first storage device to the second storage device. Migrating data from the first storage device to the second storage device is independent of any I/O operations by the host. A data write operation from the host is acknowledged only after the data has been successfully written to both the first storage device and the second storage device.

Abstract: Providing concurrent access to a tape volume of a tape emulation unit includes a first process generating a first attachment request to attach to the tape emulation unit, generating a first unique id corresponding to the first attachment request, a second process generating a second attachment request, different from the first attachment request, to attach to the tape emulation unit, generating a second unique id corresponding to the second attachment request, and allowing the first process to access a tape volume on the tape emulation unit using the first unique id while the second process concurrently accesses the tape volume on the tape emulation unit using the second unique id. The first process may access the tape volume for writing data to the tape volume. Only one of the processes may access the tape volume for writing data to the tape volume.

Abstract: Communicating with a tape drive emulation unit that communicates using command mode or transport mode includes the tape drive emulation unit receiving an inquiry about whether the tape drive emulation unit communicates using transport mode, the tape drive emulation unit responding to the inquiry by indicating that the tape drive emulation unit does communicate using transport mode, and the tape drive emulation unit servicing transport mode commands until receiving a release command. The tape drive emulation unit may include a front end component, a data mover/server, and a tape emulation storage device. The data mover/server may include an NFS server. A host may communicate with the tape emulation unit. The host and the tape emulation unit may be coupled using a FICON connection. A host application may send commands to the tape emulation unit and may receive commands from the tape emulation unit using command mode.

Abstract: Communicating between a first device and a second device includes the first device generating command mode control words for communication with the second device, the first device converting the command mode control words into transport mode control words prior to transmitting the control words to the second device, the first device receiving transport mode control words from the second device, and the first device converting the transport mode control words received from the second device into received command mode control words. An application running on the first device may generate command mode control words for communication with the second device. The application may directly provide command mode control words to an ssch or channel subsystem layer. The first device may convert the command mode control words into transport mode control words using an ssch or channel subsystem layer. The first device may be a host computing system.

Abstract: Cloning a running computing system includes quiescing processes running on a source computing system, saving state data of the source computing system, configuring a target computing system using the state data from the source computing system, and resuming program execution at the source computing system and the target computing system. Quiescing processes running on the source computing system may include marking all of the processes on the source computing system as non-dispatchable. All external resources may be identified for the source computing system prior to quiescing processes running on a source computing system. The external resources may include devices and files. The target computing system may access data that is also accessed by the source computing system. Data accessed by the source computing system may be cloned for access by the target computing system prior to resuming program execution. The data may be cloned using snapshot copies.

Abstract: Detecting data corruption in a storage device includes periodically examining portions of the data for unusual access patterns and/or unusual data manipulation and providing an indication in response to detecting unusual access patterns and/or unusual data manipulation. The unusual access patterns may be determined based on a number of data reads per unit time and/or a number of data writes per unit time. The number of data reads per unit time and the number of data writes per unit time may be determined using a counter of a flag that is set each time a data portion is accessed. Thresholds that are based on prior data accesses may be used to determine unusual access patterns. A user may set different thresholds for different portions of the data. A cyclic threshold may be used for cyclic access data and a level threshold may be used for non-cyclic data.

Abstract: Transferring data from a storage device to cloud service includes initiating a snapshot of the data, accessing each block of the data corresponding to the snapshot to transfer each block to the cloud service, and terminating the snapshot after all of the blocks have been transferred to the cloud service. At least some blocks of the storage device that are modified after initiating the snapshot may be copied from the storage device to a storage pool prior to modification. Only a first modification of a particular one of the blocks of the storage device may cause the particular one of the blocks to be copied to the storage pool. Accessing each block of the data may include accessing blocks of the storage pool. Modifying a particular one of the blocks of the storage device may include modifying a corresponding block of a storage pool.

Abstract: Migrating data from a first storage device to a second storage device includes coupling a host computer to the storage devices, causing the host computer to transition from performing I/O operations with the first storage device to performing I/O operations with the second storage device by modifying metadata used for I/O operations to change a mapping of logical devices to physical devices, migrating data from the first storage device to the second storage device independently of any I/O operations by the host, and acknowledging a data write operation from the host only after the data has been successfully written to both the first storage device and the second storage device. Modifying metadata may include changing control block information in device drivers. The data may be written by the host to the second storage device only and the data may be copied from the second storage device to the first storage device.

Abstract: Communicating between a first device and a second device includes a first portion of the first device generating command mode control words for communication with the second device, a second portion different from the first portion converting the command mode control words into transport mode control words prior to transmitting the control words to the second device, the second portion of the first device receiving transport mode control words from the second device, the second portion of the first device converting the transport mode control words received from the second device into received command mode control words, and the second portion of the first device providing the received command mode control words to the first portion of the first device. The first portion of the first device may be an application running on the first device. The first and second devices may be coupled using a FICON connection.

Abstract: Migrating data from a first storage device to a second storage device includes causing all data of the first storage device to be copied from the first storage device to the second storage device and causing the host computer to transition from performing I/O operations with the first storage device to performing I/O operations with the second storage device by modifying metadata used for I/O operations to change a mapping of logical devices to physical devices only after causing all data of the first storage device to be copied from the first storage device to the second storage device. Migrating data from the first storage device to the second storage device is independent of any I/O operations by the host. A data write operation from the host is acknowledged only after the data has been successfully written to both the first storage device and the second storage device.

Abstract: Migrating data from a first storage device to a second storage device includes coupling a host computer to the storage devices, causing the host computer to transition from performing I/O operations with the first storage device to performing I/O operations with the second storage device by modifying metadata used for I/O operations to change a mapping of logical devices to physical devices, migrating data from the first storage device to the second storage device independently of any I/O operations by the host, and acknowledging a data write operation from the host only after the data has been successfully written to both the first storage device and the second storage device. Modifying metadata may include changing control block information in device drivers. The data may be written by the host to the second storage device only and the data may be copied from the second storage device to the first storage device.

Abstract: Accessing a portion of data that was previously migrated to a cloud service includes initiating a recall of the data from the cloud service in response to the data residing entirely on the cloud service, determining if the portion of the data is stored on the storage device, retrieving cloud objects from the cloud service corresponding to the portion of the data in response to the portion of the data being unavailable on the storage device, and accessing the portion of the data on the storage device while cloud objects corresponding to other portions of the data are being transferred from the cloud service to the storage device. The host may receive a migrated status indicator in response to the data existing entirely on the cloud service. Initiating the recall may include modifying metadata to indicate that the data is available for access by the host.

Abstract: Restoring data from a storage device to a cloud service includes initializing each of a plurality of flags for each of portions of the data when the data is initially recalled from the cloud service to the storage device, the flags indicating whether a corresponding portion of the data has been modified while being stored on the storage device, modifying a particular one of the flags in response to a corresponding one of the portions being modified, transferring only portions of the data having corresponding flags that have been modified to migrate, and merging the portions of the data with remaining data at the cloud service. Data that is recalled from the cloud service to the storage device may be maintained on the cloud service. The portions of data that are transferred from the storage device to the cloud service may overwrite data maintained at the cloud service.

Abstract: Causing data in an in-band storage device coupled to a host computing system to be transferred to an out-of-band (OOB) storage device includes coupling the in-band storage device to the OOB storage device, the in-band storage device detecting commands from the host computing system to transfer the data in the in-band storage device to a cloud storage, and the in-band storage device transferring the data in the in-band storage device to the to the OOB storage device in response to receiving a command from the host computing system to transfer the data in the in-band storage device to the cloud storage. The OOB storage device may be coupled to the cloud storage. Causing data in an in-band storage device to be transferred to an OOB storage device may also include causing data stored at the OOB storage device to be transferred to the cloud storage.