Abstract: Copying data from a source storage system to a target storage system includes resetting a write tracker on the source storage system to track writes to the source storage system by one or more host computing systems, copying data from the source storage system to the target storage system after resetting the write tracker, suspending writes to the source storage system after copying the data, and copying data portions of the source storage system to the target storage system that are indicated as being written by the write tracker after suspending writes to the source storage system. Applications that write data to the source storage system may be quiesced in connection with suspending writes to the source storage system. Data portions may be repeatedly copied from the source storage system to the target storage system until an end condition is reached.

Abstract: Handling I/O operations between a storage system and a host includes initiating a direct data transfer for each of the I/O operations that initially excludes other processes from using a CPU of the host, setting a first timer for each of the direct data transfers, converting at least some of the direct transfers to semi-synchronous I/O operations that release the CPU for use by other processes and transfer data directly between the storage system and the host in response to the first timer expiring prior to completion of a corresponding one of the direct data transfers, and setting a second timer that corresponds to an expected completion of the semi-synchronous I/O operation. The direct data transfers may exchange data between the host and cache memory of the storage system. The direct data transfers may be performed using a high speed connection between the storage system and the host.

Abstract: Running an independent task in connection with a synchronous I/O operation between a storage system and a host includes starting the synchronous I/O operation, setting a timer for the synchronous I/O operation, starting the independent task that runs while waiting for completion of the synchronous I/O operation, and aborting the synchronous I/O operation in response to the timer expiring prior to completion of the synchronous I/O operation. The independent task may be ended in response to the timer expiring. The independent task may be ended in response to the I/O operation completing. The synchronous I/O operation may be performed using a high speed connection between the storage system and the host, which may be coupled to a smart network interface controller provided on a director board in the storage system. The smart network interface controller may include a system on a chip having a processor, memory, and non-volatile storage.

Abstract: A host computing system includes an applications layer containing one or more user applications that perform I/O operations, an access methods layer that communicates with the applications layer, an I/O drivers layer that communicates with the access methods layer, and an SSCH simulation layer that communicates with the I/O drivers layer and that simulates a Fibre Channel connection that is accessed by applications in the applications layer. The host computing system may also include a TCP/IP stack layer that communicates with the SSCH simulation layer to provide TCP/IP communication for the host computing system. TCP/IP communication provided by the TCP/IP stack layer may be separate from any dedicated TCP/IP communication provided by the host. The host computing system may be coupled to a TCP/IP network. A cloud storage may be coupled to the network to communicate with the host computing system.

Abstract: Using high speed data transfer protocol to transfer data between a host and a storage system includes determining if a portion of data is a candidate for being transferred using the high speed data transfer protocol if the portion is not a candidate for high speed data transfer, transferring the data using a relatively low speed data transfer protocol if the portion is a candidate for high speed data transfer, attempting to transfer the data using the high speed data transfer protocol, and if transferring the data using the high speed data transfer protocol is unsuccessful, transferring the data using the relatively low speed data transfer protocol. The high speed data transfer protocol may use a first connection and the relatively low speed data transfer protocol may use a second connection. The first connection may be a PCIe or InfiniBand connection. The second connection may be a FICON connection.

Abstract: Accessing additional storage space of a storage system includes reading a physical data fragment that is an incremental subset of a physical storage unit of the storage system, accessing metadata corresponding to logical blocks stored on the physical data fragment to determine a sidebar storage portion of the physical data fragment that is unused by the logical blocks, and accessing data of the sidebar storage portion. Accessing data of the sidebar storage portion may include providing data from the sidebar storage portion to a calling process. Accessing data of the sidebar storage portion may include modifying a portion of data from the physical data fragment and writing the physical data fragment back to the physical storage device. The physical data fragment may be locked prior to reading the physical data fragment and the physical data fragment may be unlocked after writing the physical data fragment.

Abstract: Running an independent task in connection with a synchronous I/O operation between a storage system and a host includes starting the synchronous I/O operation, setting a timer for the synchronous I/O operation, starting the independent task that runs while waiting for completion of the synchronous I/O operation, and aborting the synchronous I/O operation in response to the timer expiring prior to completion of the synchronous I/O operation. The independent task may be ended in response to the timer expiring. The independent task may be ended in response to the I/O operation completing. The synchronous I/O operation may be performed using a high speed connection between the storage system and the host, which may be coupled to a smart network interface controller provided on a director board in the storage system. The smart network interface controller may include a system on a chip having a processor, memory, and non-volatile storage.

Abstract: Handling I/O operations between a storage system and a host includes initiating a direct data transfer for each of the I/O operations that initially excludes other processes from using a CPU of the host, setting a first timer for each of the direct data transfers, converting at least some of the direct transfers to semi-synchronous I/O operations that release the CPU for use by other processes and transfer data directly between the storage system and the host in response to the first timer expiring prior to completion of a corresponding one of the direct data transfers, and setting a second timer that corresponds to an expected completion of the semi-synchronous I/O operation. The direct data transfers may exchange data between the host and cache memory of the storage system. The direct data transfers may be performed using a high speed connection between the storage system and the host.

Abstract: Directly writing snapshot data for a volume on a storage system to an external storage includes receiving a write of new data to a portion of the storage system, forming encapsulated data by encapsulating either the new data or data at the portion of the storage system in a format that is native to the storage system, and directly writing the encapsulated data to the external storage. The external storage may be cloud storage or may be a tape emulation unit. The data at the portion of the storage system may be encapsulated prior to writing the new data to the storage system. The new data may be encapsulated. Prior to receiving a write of the new data, a full backup may be performed from the storage system to the external storage. The encapsulated data may provide an incremental backup for the full backup.

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: 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: A host computing system includes an applications layer containing one or more user applications that perform I/O operations, an access methods layer that communicates with the applications layer, an I/O drivers layer that communicates with the access methods layer, and an SSCH simulation layer that communicates with the I/O drivers layer and that simulates a Fibre Channel connection that is accessed by applications in the applications layer. The host computing system may also include a TCP/IP stack layer that communicates with the SSCH simulation layer to provide TCP/IP communication for the host computing system. TCP/IP communication provided by the TCP/IP stack layer may be separate from any dedicated TCP/IP communication provided by the host. The host computing system may be coupled to a TCP/IP network. A cloud storage may be coupled to the network to communicate with the host computing system.

Abstract: Copying data from a source storage system to a target storage system includes resetting a write tracker on the source storage system to track writes to the source storage system by one or more host computing systems, copying data from the source storage system to the target storage system after resetting the write tracker, suspending writes to the source storage system after copying the data, and copying data portions of the source storage system to the target storage system that are indicated as being written by the write tracker after suspending writes to the source storage system. Applications that write data to the source storage system may be quiesced in connection with suspending writes to the source storage system. Data portions may be repeatedly copied from the source storage system to the target storage system until an end condition is reached.

Abstract: Transitioning from using a donor four site replication system to using a target four site replication system includes initiating synchronization between a first local storage system of the donor four site replication system that receives I/O from a host with an alternative first local storage system of the target four site replication system, the host switching to automatically fail over to a synchronous storage system of the target four site replication system that receives synchronous data from the alternative first local storage system following synchronizing the first local storage system with the alternative first local storage system, and the host switching to perform I/O operations with the alternative first local storage system following switching to automatically fail over to the synchronous storage system. The host may run the z/OS operating system. The host may automatically fail over to a storage system by switching subchannel sets.

Abstract: Accessing additional storage space of a storage system includes reading a physical data fragment that is an incremental subset of a physical storage unit of the storage system, accessing metadata corresponding to logical blocks stored on the physical data fragment to determine a sidebar storage portion of the physical data fragment that is unused by the logical blocks, and accessing data of the sidebar storage portion. Accessing data of the sidebar storage portion may include providing data from the sidebar storage portion to a calling process. Accessing data of the sidebar storage portion may include modifying a portion of data from the physical data fragment and writing the physical data fragment back to the physical storage device. The physical data fragment may be locked prior to reading the physical data fragment and the physical data fragment may be unlocked after writing the physical data fragment.

Abstract: Directly writing snapshot data for a volume on a storage system to an external storage includes receiving a write of new data to a portion of the storage system, forming encapsulated data by encapsulating either the new data or data at the portion of the storage system in a format that is native to the storage system, and directly writing the encapsulated data to the external storage. The external storage may be cloud storage or may be a tape emulation unit. The data at the portion of the storage system may be encapsulated prior to writing the new data to the storage system. The new data may be encapsulated. Prior to receiving a write of the new data, a full backup may be performed from the storage system to the external storage. The encapsulated data may provide an incremental backup for the full backup.

Abstract: Transitioning from using a donor four site replication system to using a target four site replication system includes initiating synchronization between a first local storage system of the donor four site replication system that receives I/O from a host with an alternative first local storage system of the target four site replication system, the host switching to automatically fail over to a synchronous storage system of the target four site replication system that receives synchronous data from the alternative first local storage system following synchronizing the first local storage system with the alternative first local storage system, and the host switching to perform I/O operations with the alternative first local storage system following switching to automatically fail over to the synchronous storage system. The host may run the z/OS operating system. The host may automatically fail over to a storage system by switching subchannel sets.

Abstract: Changing operational backup parameters on a storage system includes a first actor generating a request to change operational backup parameters, providing the request from the first actor to a second actor, the second actor authorizing the request, and modifying the operational backup parameters in response to the second actor authorizing the request. The first actor may be assigned a role that allows the first actor to generate the request to change operational backup parameters of the storage system and the second actor may be assigned a role that allows the second actor to authorize the request to change operational backup parameters of the storage system. The request may include a time window provided by the first actor. Authorizing a request to change operational backup parameters of the storage system may create a token and an authorization key. The token may be indicative of the request provided by the first actor.

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: 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.