Abstract: Techniques are provided for load balancing in a storage system using a storage system-driven host connectivity management process. For example, a load balancing process comprises monitoring a distribution of input/output (I/O) workload across resources of a storage system to detect for an occurrence of an I/O workload imbalance, generating updated connection information for a host system connected to the storage system, in response to detecting the occurrence of an I/O workload imbalance, and sending a request to the host system to discover the updated connection information for connecting to the storage system based on the updated connection information.

Abstract: An apparatus includes at least one processing device configured to identify a logical storage volume stored across multiple storage nodes of a distributed storage system, to obtain address range distribution information for the logical storage volume from at least a subset of the storage nodes, the address range distribution information indicating, for each of a plurality of distinct address ranges of the logical storage volume, which of the storage nodes locally stores data for that address range, and to generate, from the obtained address range distribution information, a mapping of the distinct address ranges to particular ones of the storage nodes, wherein the mapping is utilized to select paths for delivery of input-output operations to the storage nodes. Obtaining address range distribution information for the logical storage volume may comprise, for example, sending log page commands to each of the storage nodes to obtain asymmetric range access and/or template information.

Abstract: A first storage system receives a request to migrate a volume from the first storage system to a second storage system, and commences a migration process to non-disruptively migrate the volume from the first storage system to the second storage system while the volume is being accessed by a host system. The first storage system sends a first request to the host system to discover information for connecting to the second storage system to allow the host system to access to the volume through the second storage system during the migration process. In addition, the first storage system sends a second request to the host system to discover information for disconnecting from the first storage system during a final stage of the migration process.

Abstract: Techniques are provided for load balancing in a storage system using a storage system-driven host connectivity management process. For example, a load balancing process comprises monitoring a distribution of input/output (I/O) workload across resources of a storage system to detect for an occurrence of an I/O workload imbalance, generating updated connection information for a host system connected to the storage system, in response to detecting the occurrence of an I/O workload imbalance, and sending a request to the host system to discover the updated connection information for connecting to the storage system based on the updated connection information.

Abstract: Techniques are provided for storage system interface discovery with a limited number of persistent host discovery connections. One method comprises receiving, by a receiving storage system interface of multiple storage system interfaces, a discovery connection request from a given host interface; transforming, by the receiving storage system interface, an identifier of a host device associated with the given host interface to obtain an identifier of a given storage system interface; determining, by the receiving storage system interface, whether the identifier of the given storage system interface identifies the receiving storage system interface; and in response to the identifier of the given storage system interface identifying the receiving storage system interface, the receiving storage system interface (i) provides a persistent discovery connection to the given host interface; and (ii) provides discovery information to the given host interface identifying a set of available storage system interfaces.

Abstract: A system for managing storage of data in composed information handling systems includes a system control processor manager that identifies a compute resource set having compute resources specified by a composition request, identifies a hardware resource set having hardware resources specified by the composition request including a local data processor that services writes using a local device and a remote device, sets up storage management services for managing writes of data to the hardware resource set using a control resource set and the compute resource set to obtain logical hardware in which the local data processor preferentially services writes of the data using the local device rather than the remote device, and presents the logical hardware resources using the control resource set to the compute resource set as bare metal resources to instantiate a composed information handling system to service the composition request.

Abstract: Techniques are provided for generating host connectivity plans with load balancing and resiliency. One method comprises obtaining a number of storage system target ports needed for a given host; identifying available target ports in the storage system and an input-output (IO) target component associated with each available target port; and calculating the host connectivity plan until the host connectivity plan includes the obtained number of target ports by: (i) selecting at least one IO target component not already in the host connectivity plan that satisfies a resiliency policy and/or a load balancing policy; (ii) selecting at least one target port associated with the selected at least one IO target component and (iii) adding the selected at least one target port to the host connectivity plan. The resiliency policy may require connectivity without a single point of failure. The load balancing policy may specify that the IO target components serve a substantially equal IO load.

Abstract: A system for managing storage of data in composed information handling systems includes a system control processor manager that identifies a compute resource set having compute resources specified by a composition request, identifies a hardware resource set having hardware resources specified by the composition request including a local data processor that services writes using a local device and a remote device, sets up storage management services for managing writes of data to the hardware resource set using a control resource set and the compute resource set to obtain logical hardware in which the local data processor preferentially services writes of the data using the local device rather than the remote device, and presents the logical hardware resources using the control resource set to the compute resource set as bare metal resources to instantiate a composed information handling system to service the composition request.

Abstract: A method and system may reconstruct data in a smart storage array where upon detection of data inconsistency, an application of the system is notified and affected data strips are rebuilt. When an initiator detects stripe corruption, the initiator may report the strip corruption to storage. The storage may lock the strip for I/O operations. Initiators may determine recovery scenarios for rebuilding the data strips and send the scenarios to storage. At storage, initiator replies may be collected, and a rebuild option with the highest votes may be automatically determined for a reconstruction operation. Once the reconstruction operation is completed, the rebuilt stripe may be unlocked and data operations may recommence.

Abstract: A method and system may reconstruct data in a smart storage array where upon detection of data inconsistency, an application of the system is notified and affected data strips are rebuilt. When an initiator detects stripe corruption, the initiator may report the strip corruption to storage. The storage may lock the strip for I/O operations. Initiators may determine recovery scenarios for rebuilding the data strips and send the scenarios to storage. At storage, initiator replies may be collected, and a rebuild option with the highest votes may be automatically determined for a reconstruction operation. Once the reconstruction operation is completed, the rebuilt stripe may be unlocked and data operations may recommence.

Abstract: Provided are a computer program product, system, and method for prefetching data blocks from a primary storage to a secondary storage system while data is being synchronized between the primary storage and secondary storage. A determination is made of data blocks to prefetch from the primary storage to the secondary controller not yet synchronized from the primary storage to the secondary storage in anticipation of future access requests for the data blocks to the secondary controller while data blocks are being synchronized between the primary storage and the secondary storage over the network. A prefetch command is sent to prefetch the determined data blocks to copy from the primary storage to the secondary controller to make available to future access requests received at the secondary controller for the determined data blocks.

Abstract: Provided are a computer program product, system, and method for prefetching data blocks from a primary storage to a secondary storage system while data is being synchronized between the primary storage and secondary storage. A determination is made of data blocks to prefetch from the primary storage to the secondary controller not yet synchronized from the primary storage to the secondary storage in anticipation of future access requests for the data blocks to the secondary controller while data blocks are being synchronized between the primary storage and the secondary storage over the network. A prefetch command is sent to prefetch the determined data blocks to copy from the primary storage to the secondary controller to make available to future access requests received at the secondary controller for the determined data blocks.

Abstract: For preventing implementation errors due to misconfigured host applications, a storage controller provisions a storage destination with a capability identifier configured to indicate that the storage destination mandates atomic write operations. The storage controller also receives a write request for the storage destination from host application, and rejects, in response to the received request including a non-atomic write operation, the non-atomic write request.

Abstract: For preventing implementation errors due to misconfigured host applications, a storage controller provisions a storage destination with a capability identifier configured to indicate that the storage destination mandates atomic write operations. The storage controller also receives a write request for the storage destination from host application, and rejects, in response to the received request including a non-atomic write operation, the non-atomic write request.

Abstract: A method for accessing data in a multi-generation database is provided. The method comprises receiving a request to access first data in the database, wherein the first data is located on a first page of the database; reading an entry corresponding to the first page to locate a first track on the first page to access a newest version of the data; acquiring a first lock to synchronize accesses to the first track; and determining that the first track stores the newest version of the data, in response to reading the entry while holding the first lock.

Abstract: A novel and useful mechanism and method for writing data updates to a data cache subsystem of a storage controller. Updates received by the storage controller requiring storage allocation on a repository volume are delayed prior to being written to the data cache subsystem. The delay is based on the storage utilization of the repository volume. As the utilization of the repository volume increases, the cache write delay increases, thereby limiting the possibility that there will still be any updates in the data cache subsystem waiting to be destaged to the repository volume when the repository volume is fully utilized. When the repository volume is fully utilized all writes to the data cache of updates that will cause destage of tracks in the repository volume are stopped, thereby causing an infinite delay.

Abstract: A method for deleting a relation between a source and a target in a multi-target architecture is described. The multi-target architecture includes a source and multiple space-efficient (SE) targets mapped thereto. In one embodiment, such a method includes initially identifying a relation for deletion from the multi-target architecture. A space-efficient (SE) target associated with the relation is then identified. A mapping structure maps data in logical tracks of the SE target to physical tracks of a repository. The method then identifies a sibling SE target that inherits data from the SE target. Once the SE target and the sibling SE target are identified, the method modifies the mapping structure to map the data in the physical tracks of the repository to the logical tracks of the sibling SE target. The relation is then deleted between the source and the SE target.

Abstract: Techniques are provided for performing a copy operation. A fast reverse restore command indicating a new source and a new target is received, wherein the new source is an original target and the new target is an original source. A synchronous scan is performed on the new target. A new target structure associated with the new target is updated using a new source structure associated with the new source. Techniques are also provided for performing a copy operation in which a fast reverse restore command is received after an instant virtual copy has been performed from a new target to a new source and wherein the fast reverse restore command is performed before a background copy has been performed by the instant virtual copy.

Abstract: Techniques are provided for performing a copy operation. A fast reverse restore command indicating a new source and a new target is received, wherein the new source is an original target and the new target is an original source. A synchronous scan is performed on the new target. A new target structure associated with the new target is updated using a new source structure associated with the new source. Techniques are also provided for performing a copy operation in which a fast reverse restore command is received after an instant virtual copy has been performed from a new target to a new source and wherein the fast reverse restore command is performed before a background copy has been performed by the instant virtual copy.

Abstract: A novel and useful mechanism and method for writing data updates to a data cache subsystem of a storage controller. Updates received by the storage controller requiring storage allocation on a repository volume are delayed prior to being written to the data cache subsystem. The delay is based on the storage utilization of the repository volume. As the utilization of the repository volume increases, the cache write delay increases, thereby limiting the possibility that there will still be any updates in the data cache subsystem waiting to be destaged to the repository volume when the repository volume is fully utilized. When the repository volume is fully utilized all writes to the data cache of updates that will cause destage of tracks in the repository volume are stopped, thereby causing an infinite delay.