Abstract: Provided are a computer program product, system, and method for determining whether to process a host request using a machine learning module. Information that relates to at least one of running tasks, mail queue messages related to host requests, Input/Output (I/O) request processing, and a host request received from the host system is provided to a machine learning module. An output representing a processing load in a system is received from the machine learning module. The output is used to determine whether to process the host request.

Abstract: Provided are a computer program product, system, and method for determining whether to process a host request by training a machine learning module. A machine learning module receives input information related to at least one of running tasks, mail queue messages related to host request processing, I/O request processing, and a host request received from a host system and produces output for the host request indicating whether to process the host request. A determination is made of output produced from the machine learning module based on the input information for a received host request. A determination is made of an expected output based on a measured system resource usage and an optimum system resource usage. The machine learning module is retrained with the input information, the output produced from the machine learning module, and the expected output and provided to determine whether to process a received host request.

Abstract: Provided are a computer program product, system, and method for using a track format code in a cache control block for a track in a cache to process read and write requests to the track in the cache. A track format table associates track format codes with track format metadata. A determination is made as to whether the track format table has track format metadata matching track format metadata of a track staged into the cache. A determination is made as to whether a track format code from the track format table for the track format metadata in the track format table matches the track format metadata of the track staged. A cache control block for the track being added to the cache is generated including the determined track format code when the track format table has the matching track format metadata.

Abstract: Provided are a computer program product, system, and method for using a track format code in a cache control block for a track in a cache to process read and write requests to the track in the cache. A track format table associates track format codes with track format metadata. A determination is made as to whether the track format table has track format metadata matching track format metadata of a track staged into the cache. A determination is made as to whether a track format code from the track format table for the track format metadata in the track format table matches the track format metadata of the track staged. A cache control block for the track being added to the cache is generated including the determined track format code when the track format table has the matching track format metadata.

Abstract: A storage controller receives a plurality of synchronous writes from a host via a bus interface, wherein each of the synchronous writes is received for writing to a first node and a second node of the storage controller. For each record of a track written to the first node and the second node, an error detecting code is computed on writing the record. In response to determining that computed error detecting codes do not match for any corresponding records of the track in the first node and the second node, an indication of an error is transmitted from the storage controller to the host.

Abstract: A storage controller receives a plurality of synchronous writes from a host via a bus interface, wherein each of the synchronous writes is received for writing to a first node and a second node of the storage controller. For each record of a track written to the first node and the second node, an error detecting code is computed on writing the record. In response to determining that computed error detecting codes do not match for any corresponding records of the track in the first node and the second node, an indication of an error is transmitted from the storage controller to the host.

Abstract: Write transfer resource management in a data storage system in accordance with the present description includes overdue write transfer management logic which detects whether or not an established write set has become stale. In one embodiment, a determination is made as a function of whether a write transfer from a host and associated with an established write transfer set is overdue as measured by a time-out period of time. Upon determination that an established write transfer set has become stale, the stale write set is removed and the resources associated with the removed write set are freed for use by other write sets, significantly improving system performance. Other features and aspects may be realized, depending upon the particular application.

Abstract: Provided are a computer program product, system, and method for processing a chain of a plurality of write requests including a commit wait flag and plurality of write requests, wherein each write request group includes write transactions directed to the storage. A determination is made as to whether the commit wait flag has a first value or a second value. The write requests are processed by requiring a current write request comprising one of the write requests being processed to complete before beginning to write data for a next write request following the current write request in the write request chain in response to the commit wait flag having the first value. The write requests are processed by processing the next write request before completing the current write request in response to the commit wait flag having the second value.

Abstract: Provided are a computer program product, system, and method for generating a chain of a plurality of write requests including a commit wait flag and plurality of write requests. The commit wait flag is set to one of an indicated first value or a second value. The commit wait flag is set to the first value to cause a storage server to process the write requests by requiring a current write request being processed to complete before transferring data for a next write request following the current write request. The commit wait flag is set to the second value to cause the storage server to process the write requests by transferring data for the next write request before completing the current write request preceding the next write request. The write request chain is sent to the storage server to apply the write requests to the storage.

Abstract: A metadata track stores metadata corresponding to both a first customer data track and a second customer data track. In response to receiving a first request to perform a write on the first customer data track from a two track write process, exclusive access to the first customer data track is provided to the first request, and shared access to the metadata track is provided to the first request. In response to receiving a second request to perform a write on the second customer data track from the two track write process, exclusive access to the second customer data track is provided to the second request, and shared access to the metadata track is provided to the second request prior to providing exclusive access to the metadata track to at least one process that is waiting for exclusive access to the metadata track.

Abstract: Embodiments of the present disclosure may relate to methods and a computer program product for allowing writes based on a granularity level. The method for a storage server may include receiving a received granularity level for a particular volume of a storage device of a client computer including an effective duration for the received granularity level. The method may include receiving an anticipated write to the particular volume at an anticipated write granularity level. The method may include verifying whether the anticipated write granularity level substantially matches the received granularity level at the effective duration. The method may also include writing, in response to the anticipated write granularity level substantially matching the received granularity level at the effective duration, the anticipated write to the particular volume for the received granularity level.

Abstract: Provided are a computer program product, system, and method for processing a write of records to maintain atomicity for writing a defined group of records to multiple tracks. A write is received comprising defined groups of records to write to a plurality of tracks in the primary storage system. Sub-writes are generated to write the records in the defined groups in the write. At least one of the sub-writes includes records to write for at least one of the defined groups that spans multiple tracks in response to determining that at least one of the defined groups includes records that will be written to multiple tracks. The sub-writes are transmitted to the primary storage system to mirror to the secondary storage system to cause the secondary storage system to return complete in response to completing writing to all the tracks written to by the sub-write.

Abstract: Provided are a computer program product, system, and method for mirroring writes of records to maintain atomicity for writing a defined group of records to multiple tracks. Sub-writes are received from a host system to write records in defined groups in a write, wherein at least one of the sub-writes includes records to write for at least one of the defined groups that spans multiple tracks. For each of the sub-writes including records for at least one of the defined groups that spans multiple tracks, the tracks in the sub-write with to the secondary storage system to cause the secondary storage system to apply the tracks upon receiving all the tracks for the sub-write. Complete is returned for the sub-write to the host system upon receiving confirmation from the secondary storage system that all the tracks for the sub-write have been applied to the secondary storage system.

Abstract: Provided are a computer program product, system, and method for generating a chain of a plurality of write requests including a commit wait flag and plurality of write requests. The commit wait flag is set to one of an indicated first value or a second value. The commit wait flag is set to the first value to cause a storage server to process the write requests by requiring a current write request being processed to complete before transferring data for a next write request following the current write request. The commit wait flag is set to the second value to cause the storage server to process the write requests by transferring data for the next write request before completing the current write request preceding the next write request. The write request chain is sent to the storage server to apply the write requests to the storage.

Abstract: Provided are techniques for handling cache and Non-Volatile Storage (NVS) out of sync writes. At an end of a write for a cache track of a cache node, a cache node uses cache write statistics for the cache track of the cache node and Non-Volatile Storage (NVS) write statistics for a corresponding NVS track of an NVS node to determine that writes to the cache track and to the corresponding NVS track are out of sync. The cache node sets an out of sync indicator in a cache data control block for the cache track. The cache node sends a message to the NVS node to set an out of sync indicator in an NVS data control block for the corresponding NVS track. The cache node sets the cache track as pinned non-retryable due to the write being out of sync and reports possible data loss to error logs.

Abstract: Provided are a computer program product, system, and method for managing access requests from a host to tracks in storage. A cursor is set to point to a track in a range of tracks established for sequential accesses. Cache resources are accessed for the cache for tracks in the range of tracks in advance of processing access requests to the range of tracks. Indication is received of a subset of tracks in the range of tracks for subsequent access transactions and a determination is made whether the cursor points to a track in the subset of tracks. The cursor is set to point to a track in the subset of tracks and cache resources are accessed for tracks in the subset of tracks for anticipation of access transactions to tracks in the subset of tracks.

Abstract: A metadata track stores metadata corresponding to both a first customer data track and a second customer data track. In response to receiving a first request to perform a write on the first customer data track from a two track write process, exclusive access to the first customer data track is provided to the first request, and shared access to the metadata track is provided to the first request. In response to receiving a second request to perform a write on the second customer data track from the two track write process, exclusive access to the second customer data track is provided to the second request, and shared access to the metadata track is provided to the second request prior to providing exclusive access to the metadata track to at least one process that is waiting for exclusive access to the metadata track.

Abstract: Provided are a computer program product, system, and method for managing access requests from a host to tracks in storage. A cursor is set to point to a track in a range of tracks established for sequential accesses. Cache resources are accessed for the cache for tracks in the range of tracks in advance of processing access requests to the range of tracks. Indication is received of a subset of tracks in the range of tracks for subsequent access transactions and a determination is made whether the cursor points to a track in the subset of tracks. The cursor is set to point to a track in the subset of tracks and cache resources are accessed for tracks in the subset of tracks for anticipation of access transactions to tracks in the subset of tracks.

Abstract: Provided are techniques for handling cache and Non-Volatile Storage (NVS) out of sync writes. At an end of a write for a cache track of a cache node, a cache node uses cache write statistics for the cache track of the cache node and Non-Volatile Storage (NVS) write statistics for a corresponding NVS track of an NVS node to determine that writes to the cache track and to the corresponding NVS track are out of sync. The cache node sets an out of sync indicator in a cache data control block for the cache track. The cache node sends a message to the NVS node to set an out of sync indicator in an NVS data control block for the corresponding NVS track. The cache node sets the cache track as pinned non-retryable due to the write being out of sync and reports possible data loss to error logs.

Abstract: In response to determining, by a storage controller, that a first process is to perform a write operation, a customer data track in a cache is configured for exclusive access while waiting for the write operation on the customer data track to be performed by the first process. In response to configuring the customer data track for the exclusive access, a copy of a metadata track is generated, wherein the metadata track stores metadata information of the customer data track and is configured for shared access. The copy of the metadata track is configured to provide exclusive access to a second process to perform operations on the copy of the metadata track, wherein the first process is able to perform the write operation on the customer data track that causes the metadata track to be updated while the second process performs the operations on the copy of the metadata track.