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.

Abstract: A method is disclosed to ensure that components in a complex system are correctly connected together. In one embodiment, such a method captures a visual image of a system made up of multiple components connected together with cables. The method analyzes the visual image to determine connections between the components. The method further builds a current model that represents the connections between the components. This current model is then compared to a previous model to find differences between the current model and the previous model. If differences exist, the method notifies a user of the differences. This may assist the user in identifying any incorrect connections between the components. A corresponding apparatus and computer program product are also disclosed.

Abstract: A method is disclosed to ensure that components in a complex system are correctly connected together. In one embodiment, such a method captures a visual image of a system made up of multiple components connected together with cables. The method analyzes the visual image to determine connections between the components. The method further builds a current model that represents the connections between the components. This current model is then compared to a previous model to find differences between the current model and the previous model. If differences exist, the method notifies a user of the differences. This may assist the user in identifying any incorrect connections between the components. A corresponding apparatus and computer program product are also disclosed.

Abstract: Provided are techniques for selecting a disconnect from different types of channel disconnects using a machine learning module. An Input/Output (I/O) operation is received from a host via a channel. Inputs are provided to a machine learning module. An output is received from the machine learning module. Based on the output, one of no disconnect from the channel, a logical disconnect from the channel, or a physical disconnect from the channel is selected.

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 updating a track format table used to provide track format codes for cache control blocks with more frequently accessed track format metadata. A track format table associates track format codes with track format metadata. Each instance of the track format metadata indicates a layout of data in a track. Cache control blocks for tracks in the cache include track format codes associated with the track format metadata of the tracks in the cache. Track format access information indicating accesses of track format metadata not included in the track format table. Track format metadata, indicated in the track format access information that is not in the track format table, is added to the track format table to associate with a track format code based on a number of accesses of the track format metadata indicated in the track format access information.

Abstract: Provided are a computer program product, system, and method for managing cache segments between a global queue and a plurality of local queues using a machine learning module. Cache segment management information related to management of segments in the local queues and accesses to the global queue to transfer cache segments between the local queues and the global queue, are provided to a machine learning module to output an optimum number parameter comprising an optimum number of segments to maintain in a local queue and a transfer number parameter comprising a number of cache segments to transfer between a local queue and the global queue. The optimum number parameter and the transfer number parameter are sent to a processing unit having a local queue to cause the processing unit to transfer the transfer number parameter of cache segments between the local queue to the global queue.

Abstract: Provided are a computer program product, system, and method for managing cache segments between a global queue and a plurality of local queues by training a machine learning module. A machine learning module is provided input comprising cache segment management information related to management of segments in the local queues by the processing units and accesses of the global queue to transfer cache segments between the local queues and the global queue to output an optimum number parameter comprising an optimum number of segments to maintain in a local queue and a transfer number parameter comprising a number of cache segments to move between a local queue and the global queue. The machine learning module is retrained based on the cache segment management information to output an adjusted transfer number parameter and an adjusted optimum number parameter for the processing units.

Abstract: A method for improving cache hit ratios for selected volumes when using synchronous I/O is disclosed. In one embodiment, such a method includes establishing, in cache, a first set of non-favored storage elements from non-favored storage areas. The method further establishes, in the cache, a second set of favored storage elements from favored storage areas. The method calculates a life expectancy for the non-favored storage elements to reside in the cache prior to eviction. The method further executes an eviction policy for the cache wherein the favored storage elements are maintained in the cache for longer than the life expectancy of the non-favored storage elements. A corresponding system and computer program product are also disclosed.

Abstract: A method for improving cache hit ratios for selected volumes within a storage system is disclosed. In one embodiment, such a method includes monitoring I/O to multiple volumes residing on a storage system. The storage system includes a cache to store data associated with the volumes. The method determines, from the I/O, which particular volumes of the multiple volumes would benefit the most if provided favored status in the cache. The favored status provides increased residency time in the cache to the particular volumes compared to volumes not having the favored status. The method generates a list of the particular volumes and transmits the list to the storage system. The storage system, in turn, provides increased residency time to the particular volumes in accordance with their favored status. A corresponding system and computer program product are also disclosed.

Abstract: A method for improving cache hit ratios for selected volumes within a storage system includes monitoring I/O to multiple volumes residing on a storage system. The method determines, from the I/O, which particular volumes of the multiple volumes would benefit the most if provided favored status in cache of the storage system, where the favored status provides increased residency time in the cache compared to volumes not having the favored status. The method determines, from the I/O, an amount by which the increased residency time should exceed a residency time of volumes not having the favored status. The method generates an indicator that is representative of the amount and transmits this indicator to the storage system. The storage system, in turn, provides increased residency time to the particular volumes in accordance with the favored status and indicator. A corresponding system and computer program product are also disclosed.

Abstract: A method for improving cache hit ratios for selected storage elements within a storage system is disclosed. In one embodiment, such a method includes storing, in a cache of a storage system, non-favored storage elements and favored storage elements. The favored storage elements are retained in the cache longer than the non-favored storage elements. The method maintains a first LRU list containing entries associated with non-favored storage elements and designating an order in which the non-favored storage elements are evicted from the cache, and a second LRU list containing entries associated with favored storage elements and designating an order in which the favored storage elements are evicted from the cache. The method moves entries between the first LRU list and the second LRU list as favored storage elements are changed to non-favored storage elements and vice versa. A corresponding system and computer program product are also disclosed.

Abstract: A method for improving cache hit ratios for selected volumes within a storage system is disclosed. In one embodiment, such a method includes storing, in a cache of a storage system, non-favored storage elements and favored storage elements. The favored storage elements are retained in the cache longer than the non-favored storage elements. The method maintains a “non-favored” LRU list that contains entries associated with non-favored storage elements and designates an order in which the non-favored storage elements are evicted from the cache. The method also maintains one or more “favored” LRU lists that contain entries associated with favored storage elements and designate an order in which the favored storage elements are evicted from the cache. Each “favored” LRU list is associated with favored storage elements that have a different preferred residency time in the cache. A corresponding system and computer program product are also disclosed.

Abstract: Provided are a computer program product, system, and method for updating a track format table used to provide track format codes for cache control blocks with more frequently accessed track format metadata. A track format table associates track format codes with track format metadata. Each instance of the track format metadata indicates a layout of data in a track. Cache control blocks for tracks in the cache include track format codes associated with the track format metadata of the tracks in the cache. Track format access information indicating accesses of track format metadata not included in the track format table. Track format metadata, indicated in the track format access information that is not in the track format table, is added to the track format table to associate with a track format code based on a number of accesses of the track format metadata indicated in the track format access information.

Abstract: Provided are a method, system, and computer program product in which a storage controller receives a first write command with a first token over a first interface from a host computational device. In response to a failure of the first write command in the storage controller, the storage controller retains selected resources for reuse for a retry of the first write command, wherein the retry of the first write command is expected from the host computational device over a second interface that is a slower communication link than the first interface. In response to receiving, by the storage controller, a second write command with a second token over the second interface, wherein the second token is identical to the first token, the storage controller determines that the second write command is a retry of the first write command and reuses the retained selected resources for executing the second write command.

Abstract: A host computational device transmits a first write command with a first token over a first interface to a storage controller. In response to receiving an indication by the host computational device that the first write command has failed in the storage controller, the host computational device transmits a second write command with a second token over a second interface to the storage controller, wherein the second write command is a retry of the first write command that failed, wherein the second token is identical to the first token, and wherein the second interface is a slower communication link than the first interface.

Abstract: Provided are techniques for synchronously performing commit records operations. A local copy of a commit records message is built for a Non-Volatile Storage (NVS) track, with a valid indicator set to indicate that this commit records message is valid and has not been processed yet. A Direct Memory Access (DMA) chain is executed to transfer customer data from a host to real segments and alternate segments of a track buffer and to transfer the local copy of the commit records message to a mail message structure of a mail message array. At DMA completion, an NVS manager is synchronously called to perform a commit records operation with the commit records message in the mail message structure. In response to the commit records operation completing, there is an indication that a new write DMA is allowed to proceed for the NVS track.

Abstract: Provided are techniques for selecting a disconnect by training a machine learning module. A machine learning module is provided that receives inputs and produces an output. The output produced from the machine learning module based on the inputs for the first I/O operation and an estimated amount of time to acquire resources for a first I/O operation is determined. An actual amount of time to acquire resources for the first I/O operation is determined. The machine learning module is retrained based on the inputs, the output, and the actual amount of time it took to acquire resources for the first I/O operation versus an estimated amount of time to acquire the resources for the first I/O operation. The retrained machine learning module is used to select one of disconnect from a channel, the logical disconnect from the channel, or the physical disconnect from the channel for a second I/O operation.

Abstract: Provided are techniques for selecting a disconnect from different types of channel disconnects using a machine learning module. An Input/Output (I/O) operation is received from a host via a channel. Inputs are provided to a machine learning module. An output is received from the machine learning module. Based on the output, one of no disconnect from the channel, a logical disconnect from the channel, or a physical disconnect from the channel is selected.

Abstract: A method for removing stale messages from a storage controller is disclosed. In one embodiment, such a method includes querying, by a host system, a storage controller to determine ownership of a lock on the storage controller. The host system receives, in response to the query, information indicating that the lock has been granted to the host system. This allows the host system to treat the lock as being granted even though the host system has not received a “lock granted” message from the storage controller. Before using the lock, the host system sends, to the storage controller, an instruction to clear any stale messages on the storage controller related to the lock. A corresponding system and computer program product are also disclosed.