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 processing cache miss rates to determine memory space to add to an active cache to reduce a cache miss rate for the active cache. During caching operations to the active cache, information is gathered on an active cache miss rate based on a rate of access to tracks that are not indicated in the active cache list and a cache demote rate. A determination is made as to whether adding additional memory space to the active cache would result in the active cache miss rate being less than the cache demote rate when the active cache miss rate exceeds the cache demote rate. A message is generated indicating to add the additional memory space when adding the additional memory space would result in the active cache miss rate being less than the cache demote rate.

Abstract: A list of a first type of tracks in a cache is generated. A list of a second type of tracks in the cache is generated, wherein I/O operations are completed relatively faster to the first type of tracks than to the second type of tracks. A determination is made as to whether to demote a track from the list of the first type of tracks or from the list of the second type of tracks.

Abstract: In one embodiment, a method includes determining a plurality of hardware components of a system. The method also includes power cycling a first hardware component of the plurality of hardware components of the system according to a dynamic schedule. A period of time in which power cycling of the first hardware component takes place is shortened as the age of the first hardware component approaches the expected lifespan of the first hardware component. Also, the method includes determining whether the first hardware component experienced a power-up failure resulting from the power cycling. Moreover, the method includes outputting an indication to replace and/or repair the first hardware component in response to a determination that the first hardware component experienced the power-up failure resulting from the power cycling. Other systems, methods, ad computer program products for preventing unexpected power-up failures of individual hardware components are described in accordance with more embodiments.

Abstract: Provided are a computer program product, system, and method for communicating health status when a management console is unavailable for a server in a mirror storage environment. A determination at a first server is made that a management console is unavailable over the console network. The first server determines a health status at the first server and the first storage in response to determining that the management console cannot be reached over the console network. The health status indicates whether there are errors or no errors at the first server and the first storage. The first server transmits the determined health status to the second server over a mirroring network mirroring data between the first storage and a second storage managed by the second server. The determined health status is forwarded to an administrator.

Abstract: Provided are a computer program product, system, and method for determining an optimum number of threads to make available per core in a multi-core processor complex to execute tasks. A determination is made of a first processing measurement based on threads executing on the cores of the processor chip, wherein each core includes circuitry to independently execute a plurality of threads. A determination is made of a number of threads to execute on the cores based on the first processing measurement. A determination is made of a second processing measurement based on the threads executing on the cores of the processor chip. A determination is made of an adjustment to the determined number of threads to execute based on the second processing measurement resulting in an adjusted number of threads. The adjusted number of threads on the cores is utilized to execute instructions.

Abstract: A machine learning module receives inputs comprising attributes of a storage controller, where the attributes affect failures that occur in the storage controller. In response to a failure occurring in the storage controller, a plurality of output values corresponding to a plurality of recovery mechanisms to recover from the failure in the storage controller are generated via forward propagation through a plurality of layers of the machine learning module. A margin of error is calculated based on comparing the generated output values to expected output values corresponding to the plurality of recovery mechanisms, where the expected output values are generated from an indication of a correct recovery mechanism for the failure. An adjustment is made of weights of links that interconnect nodes of the plurality of layers via back propagation to reduce the margin of error, to improve a determination of a recovery mechanism for the failure.

Abstract: A method to dynamically switch between data transfer techniques includes receiving an I/O request and computing a cost of executing the I/O request using a memory copy data transfer technique. The memory copy data transfer technique copies cache segments associated with the I/O request from cache memory to a permanently mapped memory, which is permanently mapped to a bus address window. The method also computes a cost of executing the I/O request using a memory mapping data transfer technique. The memory mapping data transfer technique temporarily maps cache segments associated with the I/O request from the cache memory to the bus address window. The method uses one of the memory copy data transfer technique and the memory mapping data transfer technique to transfer cache segments associated with the I/O request, depending on which one is less costly. A corresponding system and computer program product are also disclosed.

Abstract: A method for demoting data from a cache comprising heterogeneous memory types is disclosed. The method maintains for a data element in the cache, a write access count that is incremented each time the data element is updated in the cache. The cache includes a higher performance portion and a lower performance portion. The method also maintains, for the data element, a read access count that is incremented each time a data element is read in the cache. The method removes the data element from the higher performance portion of the cache in accordance with a cache demotion algorithm. If the write access count is below a first threshold and the read access count is above a second threshold, the method places the data element in the lower performance portion. A corresponding system and computer program product are also disclosed.

Abstract: A method for demoting data from a cache comprising heterogeneous memory types is disclosed. The method maintains, for a data element in the cache, a write access count that is incremented each time the data element is updated in the cache. The cache includes a higher performance portion and a lower performance portion. The method removes the data element from the higher performance portion in accordance with a cache demotion algorithm. If the data element also resides in the lower performance portion and the write access count is below a first threshold, the method leaves the data element in the lower performance portion. If the data element also resides in the lower performance portion and the write access count is at or above the first threshold, the method removes the data element from the lower performance portion. A corresponding system and computer program product are also disclosed.

Abstract: A method for storing metadata in a cache comprising heterogeneous memory types is disclosed. The method stages data elements containing metadata into a lower performance portion of a cache. The cache includes the lower performance portion and a higher performance portion. In response to determining that the data elements are updated in the higher performance portion, the method records when the data elements were updated and invalidates the data elements in the lower performance portion. The method scans the lower performance portion for the data elements that are invalidated and re-stages, in the lower performance portion, the data elements that are invalidated and have not been updated in the higher performance portion in a last specified period of time. A corresponding system and computer program product are also disclosed.

Abstract: In one embodiment, storage drive dependent track removal processing logic performs destage tasks for tracks cached in a cache as a function of whether the storage drive is classified as a fast class or as slow class of storage drives, for example. In one embodiment, a destage task configured for a slow class storage drive, transfers an entry for a track selected for destaging from a main cache list to a wait cache list to await destaging to the slow class drive. A destage task configured for a fast class storage drive allows the cache list entry for the selected track to remain on the main cache list while the selected track is being destaged to the fast class storage drive, thereby bypassing the transfer of the entry to a wait cache list. Other features and aspects may be realized, depending upon the particular application.

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 cache hit is generated, in response to receiving an input/output (I/O) command over a bus interface. An update for a metadata track is stored in a buffer associated with a central processing unit (CPU) that processes the I/O command, in response to generating the cache hit. The metadata track is asynchronously updated from the buffer with the stored update for the metadata track in the buffer.

Abstract: A computational device receives indications of a minimum retention time and a maximum retention time in cache for a first plurality of tracks, wherein no indications of a minimum retention time or a maximum retention time in the cache are received for a second plurality of tracks. A cache management application demotes a track of the first plurality of tracks from the cache, in response to determining that the track is a least recently used (LRU) track in a LRU list of tracks in the cache and the track has been in the cache for a time that exceeds the minimum retention time. The cache management application demotes the track of the first plurality of tracks, in response to determining that the track has been in the cache for a time that exceeds the maximum retention time.

Abstract: Provided are a computer program product, system, and method for using a machine learning module to determine when to perform error checking of a storage unit. Input on attributes of at least one storage device comprising the storage unit are provided to a machine learning module to produce an output value. An error check frequency is determined from the output value. A determination is made as to whether the error check frequency indicates to perform an error checking operation with respect to the storage unit. The error checking operation is performed in response to determining that the error checking frequency indicates to perform the error checking operation.

Abstract: Provided are a computer program product, system, and method for determining a frequency at which to execute trap code in an execution path of a process executing a program to generate a trap address range to detect potential malicious code. Trap code is executed in response to processing a specified type of command in application code to allocate a trap address range used to detect potentially malicious code. A determination is whether to modify a frequency of executing the trap code in response to processing a specified type of command. The frequency of executing the trap code is modified in response to processing the specified type of command in response to determining to determining to modify the frequency of executing the trap code.

Abstract: In one embodiment, performance-based multi-mode task dispatching for high temperature avoidance in accordance with the present description, includes selecting processor cores as available to receive a dispatched task. Tasks are dispatched to a set of available processor cores for processing in a performance-based dispatching mode. If monitored temperature rises above a threshold temperature value, task dispatching logic switches to a thermal-based dispatching mode. If a monitored temperature falls below another threshold temperature value, dispatching logic switches back to the performance-based dispatching mode. If a monitored temperature of an individual processor core rises above a threshold temperature value, the processor core is redesignated as unavailable to receive a dispatched task. If the temperature of an individual processor core falls below another threshold temperature value, the processor core is redesignated as available to receive a dispatched task.

Abstract: A computational device receives an indication of a minimum retention time in a cache for a plurality of tracks of an application. In response to determining that tracks of the application that are stored in the cache exceed a predetermined threshold in the cache, the computational device demotes one or more tracks of the application from the cache even though a minimum retention time in cache has been indicated for the one or more tracks of the application, while performing least recently used (LRU) based replacement of tracks in the cache.

Abstract: A minimum retention time in cache is indicated for a first plurality of tracks, where no minimum retention time is indicated for a second plurality of tracks. A cache management application demotes a track of the first plurality of tracks from the cache, in response to determining that the track is a least recently used (LRU) track in a LRU list of tracks in the cache and the track has been in the cache for a time that exceeds the minimum retention time.