Abstract: Transferring data between a first storage device coupled to a host computing system and a second storage device coupled to the first storage device includes the first storage device receiving a command from the host computing system, the first storage device determining if the command is an out-of-band (OOB) storage command, and, if the command is an OOB storage command, the first storage device sending a command to the second storage device to cause data to be transferred directly between the first storage device and the second storage device independent of the host computing system. Transferring data between a first storage device coupled to a host computing system and a second storage device coupled to the first storage device may also include the first storage device emulating a host computing system in connection with communicating with the second storage device. The second storage device may be a tape emulation unit.

Abstract: Described are techniques for mirroring data that may include issuing, by an application on a host, a write operation that writes first data to a primary storage entity having data stored in accordance with a first format and first structure; intercepting, on the host, the write operation; and performing, on the host, first processing to process the write operation. The first processing may include: sending the write operation to a data storage system including the primary storage entity; determining whether the primary storage entity is mirrored as a second storage entity having data stored in a second format and second structure different from the first format and first structure; and responsive to determining the primary storage entity is mirrored as the second storage entity, issuing one or more second write operations to mirror the first data on the second storage entity in accordance with the second format and second structure.

Abstract: Processing an I/O operation may include the host selecting one of the available paths over which to send each I/O operation to the data storage system. The selected path may be to a particular director that has responsibility for cache slot allocation and locally accessing the cache slot predicted to include the data of the I/O operation. The host may understand the cache slot allocation algorithm used on the data storage system and how cache slots are allocated for particular logical devices and tracks or locations on the logical devices. The host may direct I/Os down a path to a particular director that has, or will allocate, the cache slot used for the I/Os. There may be multiple directors in a data storage system including a distributed global memory. Each director may locally access a group of cache slots and communicate over a fabric to access the distributed global memory.

Abstract: Systems and procedures are provided to enable large size fixed block architecture (FBA) device support over FICON. The FBA devices may have a size greater than 2 terabytes. For example, in known storage systems, an FBA device size may be 64 terabytes and an architecture provided for 512-terabyte devices, and the described system supports such large, or even larger, FBA devices. The system may be used with existing fixed block command sets.

Abstract: Accessing at least two separate physical storage devices as a single logical device includes receiving data/metadata from both of the separate physical storage devices and causing the data/metadata to appear to be coming from only one of the storage devices by spoofing data/metadata from at least one of the storage devices to appear to be coming from the other of the storage devices. Spoofing data/metadata may include revising storage device identifiers. The storage device identifiers may include serial numbers and port identifiers.

Abstract: A high performance logical device having low latency may be provided. I/Os to the logical device may be sent only to a primary director having sole ownership of the logical device. The primary director may perform operations locally for the logical device. Such operations may include allocating global memory for use with the logical device from only a global memory portion that is local to the primary director. The global memory may be a distributed global memory including memory from multiple directors and possibly multiple engines. Cached data for the logical device may be mirrored automatically by the data storage system. Alternatively, the cached data for the logical device may be mirrored using a host-based mirroring technique.

Abstract: A high performance logical device having low latency may be provided. I/Os to the logical device may be sent only to a primary director having sole ownership of the logical device. The primary director may perform operations locally for the logical device. Such operations may include allocating global memory for use with the logical device from only a global memory portion that is local to the primary director. The global memory may be a distributed global memory including memory from multiple directors and possibly multiple engines. Cached data for the logical device may be mirrored automatically by the data storage system. Alternatively, the cached data for the logical device may be mirrored using a host-based mirroring technique.

Abstract: Multiple hardware and/or software components across the host and data storage system may be capable of performing data transformation operations. In at least one embodiment, a particular one of the multiple components may be selected, per I/O operation and using information generated by a component selection tool, to perform a data transformation operation. For an I/O operation, a first component may be selected to perform a first data transformation operation and a second different component may be selected to perform a second data transformation operation. The first and second components may both be on the host, both on the data storage system, or on different ones of the host and data storage system. A host I/O driver may create a request for the I/O operation where the request includes indicators identifying the first and second components as selected for performing the data transformation operations.

Abstract: Emulating tape data includes providing a first storage device coupled to a host, providing a tape emulation unit coupled to the host, the tape emulation unit including a data mover, and, in response to a command to transfer data between the first storage device and the tape emulation unit, transferring data directly between the first storage device and the data mover using a link therebetween, where data that is transferred bypasses the host. The tape emulation unit may include a front end component coupled to the host and a second storage device, the data mover being interposed between the second storage device and the front end component. The front end component may be coupled to the data mover using a GigE switch. The data mover may use NFS to access data. At least one of the first and second data storage devices may be data storage arrays.

Abstract: Providing I/O operations to a storage device includes selecting a portion of original I/O operations based on a first set of criteria, determining whether to subdivide each of the portion of original I/O operations that are selected according to a second set of criteria different than the first set of criteria, and converting each of the original I/O operations selected for subdivision into a plurality of subdivided I/O operations for different portions of data for a corresponding one of the original I/O operations, where at least two of the different portions are from a single track of data on the storage device. The first set of criteria may include whether the I/O operations are for multiple tracks of data and whether the storage device supports subdividing a single track. The second set of criteria may include determining a measured amount of performance improvement for previous subdivision operations.

Abstract: Providing I/O operations to a storage device includes selecting a portion of original I/O operations based on a first set of criteria, determining whether to subdivide each of the portion of original I/O operations that are selected according to a second set of criteria different than the first set of criteria, and converting each of the original I/O operations selected for subdivision into a plurality of subdivided I/O operations for different portions of data for a corresponding one of the original I/O operations. The first set of criteria may include whether the I/O operations are for multiple tracks of data. The second set of criteria may include determining a measured amount of performance improvement for previous subdivision operations. Performance of subdivided I/O operations may be monitored. A number of subdivided I/O operations may be limited by a number of available parallel I/O routes.

Abstract: Described are data replication techniques that may include receiving, on a host, a write operation that writes first data to a target location on a first logical device having storage provisioned on a first data storage system; determining, on the host and in accordance with one or more criteria, whether the first data is to be replicated on a second logical device on a second data storage system; and issuing the write operation from the host to the first data storage system, wherein the write operation denotes whether to disable replication of the first data to the second logical device on the second data storage system. Such techniques may include partitioning a single write operation into multiple write operations and setting an indicator in each of the multiple writes denoting whether remote replication of the write operation is enabled or disabled.

Abstract: Systems and techniques are provided for incremental Continuous Data Protection (iCDP) as a process to secure frequent, and space efficient, versions of consistent point-in-time images of a group of volumes using snapshot technology. The system provides for automation to create and manage frequent snapshots of defined groups of volumes. The incremental approach of the system described herein provides a convenient way to roll back to prior point-in-time versions to investigate data damage due to processing errors or other forms of corruption. Log space in log devices may be reclaimed in connection with managing recovery and roll back capabilities of the system to desired data versions for purposes of data protection. Point in time versions of a source device may be accessed through the source device. The particular point in time version accessed in servicing an I/O may be determined in accordance with one or more criteria.

Abstract: Systems and procedures are provided to enable fixed block architecture (FBA) device support over fiber connections using transport mode protocol. The FBA devices may have a size greater than 2 terabytes. The system may be used with existing fixed block command sets according to the transport mode protocol. The existing fixed block command sets may be extended to permit addressing of greater than 2 terabytes. The transport mode protocol may be based on a high performance protocol implementation that facilitates processing of I/O requests.

Abstract: Systems and techniques are provided for incremental Continuous Data Protection (iCDP) as a process to secure frequent, and space efficient, versions of consistent point-in-time images of a group of volumes using snapshot technology. The system described herein provides for automation to create and manage frequent snapshots of defined groups of volumes. The incremental approach of the system described herein provides a convenient way to roll back to prior point-in-time versions to investigate data damage due to processing errors or other forms of corruption. The intervals between versions may be controlled. The system beneficially provides for identifying, monitoring, and reclaiming use of log space in log devices in connection with managing recovery and roll back capabilities of the system to desired data versions for purposes of data protection.

Abstract: A system and method for data replication is provided. A host synchronously replicates data between a first local storage device and a second local storage device, the first local storage device and the second local storage device being coupled to the host. Data is then asynchronously replicated from the first local storage device and the second local storage device to at least one remote storage device. In an embodiment, each of the local storage devices may asynchronously replicate data to remote storage devices located at separate sites to provide four site data replication processing. The system described herein provides for advantageous and efficient swapping of control between hosts and storage devices located in different regions in response to disasters and/or other events affecting data storage in a particular region.

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: Emulating a Fiber Channel connection to a workstation includes providing a first Fiber Channel emulator that exchanges data between the workstation and a data storage device using a connection mechanism between the workstation and the data storage device, wherein the connection mechanism is incompatible with a Fiber Channel connection and handling emulator events received at the emulator, wherein the events include message events, state events, and driver events. The first Fiber Channel emulator may act as an I/O subsystem providing FICON communication capability. The connection mechanism may be an Ethernet connection. The first Fiber Channel emulator may send a message to a link layer which sends a message to an SLI driver which builds a ring queue message and passes the message to an emulated hardware layer which packages up the message indicating status. The message may be sent using the connection mechanism.

Abstract: Systems and techniques are provided for incremental Continuous Data Protection (iCDP) as a process to secure frequent, and space efficient, versions of consistent point-in-time images of a group of volumes using snapshot technology. The system described herein provides for automation to create and manage frequent snapshots of defined groups of volumes. The incremental approach of the system described herein provides a convenient way to roll back to prior point-in-time versions to investigate data damage due to processing errors or other forms of corruption. The intervals between versions may be controlled. The system beneficially provides for identifying, monitoring, and reclaiming use of log space in log devices in connection with managing recovery and roll back capabilities of the system to desired data versions for purposes of data protection.

Abstract: Emulating tape data includes providing a first storage device coupled to a host, providing a tape emulation unit coupled to the host, the tape emulation unit including a data mover, and, in response to a command to transfer data between the first storage device and the tape emulation unit, transferring data directly between the first storage device and the data mover using a link therebetween, where data that is transferred bypasses the host. The tape emulation unit may include a front end component coupled to the host and a second storage device, the data mover being interposed between the second storage device and the front end component. The front end component may be coupled to the data mover using a GigE switch. The data mover may use NFS to access data. At least one of the first and second data storage devices may be data storage arrays.