Abstract: A computing device-implemented method for implementing dynamic hierarchical memory cache (HMC) awareness within a storage system is described. Specifically, when performing dynamic read operations within a storage system, a data module evaluates a data prefetch policy according to a strategy of determining if data exists in a hierarchical memory cache and thereafter amending the data prefetch policy, if warranted. The system then uses the data prefetch policy to perform a read operation from the storage device to minimize future data retrievals from the storage device. Further, in a distributed storage environment that include multiple storage nodes cooperating to satisfy data retrieval requests, dynamic hierarchical memory cache awareness can be implemented for every storage node without degrading the overall performance of the distributed storage environment.

Abstract: Storage tracks from at least one host are destaged from the write cache rank when it is determined that the at least one host is idle with respect to a first set of ranks, and storage tracks are refrained from being destaged from each rank when it is determined that the at least one host is not idle with respect to a second set of ranks.

Abstract: Embodiments are provided for cache memory systems. In one general embodiment, a method that includes receiving a host write request from a host computer, creating a sequential log file in a storage device, and copying data received during the host write request to a storage buffer. The method further includes determining if a selected quantity of data has been accumulated in the storage buffer and executing a write through of data to sequentially write the data accumulated in the storage buffer to the sequential log file and to a storage class memory device if the selected quantity of data has been accumulated in the storage buffer.

Abstract: Storage tracks from at least one host are destaged from the write cache rank when it is determined that the at least one host is idle with respect to a first set of ranks, and storage tracks are refrained from being destaged from each rank when it is determined that the at least one host is not idle with respect to a second set of ranks.

Abstract: Storage tracks from at least one server are destaged from the write cache rank when it is determined that the at least one server is idle with respect to a first set of ranks, and storage tracks are refrained from being destaged from each rank when it is determined that the at least one server is not idle with respect to a second set of ranks such that storage tracks in the first set of ranks may be destaged while storage tracks in the second set of ranks are not being destaged.

Abstract: Storage tracks from at least one host are destaged from the write cache rank when it is determined that the at least one host is idle with respect to a first set of ranks, and storage tracks are refrained from being destaged from each rank when it is determined that the at least one host is not idle with respect to a second set of ranks such that storage tracks in the first set of ranks may be destaged while storage tracks in the second set of ranks are not being destaged.

Abstract: A computing device-implemented method for implementing dynamic hierarchical memory cache (HMC) awareness within a storage system is described. Specifically, when performing dynamic read operations within a storage system, a data module evaluates a data prefetch policy according to a strategy of determining if data exists in a hierarchical memory cache and thereafter amending the data prefetch policy, if warranted. The system then uses the data prefetch policy to perform a read operation from the storage device to minimize future data retrievals from the storage device. Further, in a distributed storage environment that include multiple storage nodes cooperating to satisfy data retrieval requests, dynamic hierarchical memory cache awareness can be implemented for every storage node without degrading the overall performance of the distributed storage environment.

Abstract: A computing device-implemented method for implementing dynamic hierarchical memory cache (HMC) awareness within a storage system is described. Specifically, when performing dynamic read operations within a storage system, a data module evaluates a data prefetch policy according to a strategy of determining if data exists in a hierarchical memory cache and thereafter amending the data prefetch policy, if warranted. The system then uses the data prefetch policy to perform a read operation from the storage device to minimize future data retrievals from the storage device. Further, in a distributed storage environment that include multiple storage nodes cooperating to satisfy data retrieval requests, dynamic hierarchical memory cache awareness can be implemented for every storage node without degrading the overall performance of the distributed storage environment.

Abstract: Described is a system and computer program product for implementing dynamic hierarchical memory cache (HMC) awareness within a storage system. Specifically, when performing dynamic read operations within a storage system, a data module evaluates a data prefetch policy according to a strategy of determining if data exists in a hierarchical memory cache and thereafter amending the data prefetch policy, if warranted. The system then uses the data prefetch policy to perform a read operation from the storage device to minimize future data retrievals from the storage device. Further, in a distributed storage environment that include multiple storage nodes cooperating to satisfy data retrieval requests, dynamic hierarchical memory cache awareness can be implemented for every storage node without degrading the overall performance of the distributed storage environment.

Abstract: In one aspect of the present description, at least one of the value of a prestage trigger and the value of the prestage amount, may be modified as a function of the drive speed of the storage drive from which the units of read data are prestaged into a cache memory. Thus, cache prestaging operations in accordance with another aspect of the present description may take into account storage devices of varying speeds and bandwidths for purposes of modifying a prestage trigger and the prestage amount. Still further, a cache prestaging operation in accordance with further aspects may decrease one or both of the prestage trigger and the prestage amount as a function of the drive speed in circumstances such as a cache miss which may have resulted from prestaged tracks being demoted before they are used.

Abstract: Storage tracks from at least one server are destaged from the write cache rank when it is determined that the at least one server is idle with respect to a first set of ranks, and storage tracks are refrained from being destaged from each rank when it is determined that the at least one server is not idle with respect to a second set of ranks such that storage tracks in the first set of ranks may be destaged while storage tracks in the second set of ranks are not being destaged.

Abstract: Storage tracks from at least one host are destaged from the write cache rank when it is determined that the at least one host is idle with respect to a first set of ranks, and storage tracks are refrained from being destaged from each rank when it is determined that the at least one host is not idle with respect to a second set of ranks such that storage tracks in the first set of ranks may be destaged while storage tracks in the second set of ranks are not being destaged.

Abstract: Storage tracks are destaged from the write cache if the host(s) is/are idle and are not destaged from the write cache if one or more of the hosts is/are not idle. The storage tracks are refrained from being destaged from the write cache if the at least one host is not idle. Each rank is monitored for write operations from the at least one host, and a determination is made if the at least one host is idle with respect to each respective rank based on monitoring each rank for write operations from the at least one host such that the at least one host may be determined to be idle with respect to a first rank and not idle with respect to a second rank.

Abstract: Destaging storage tracks from each rank that includes a greater than a predetermined percentage of a predetermined amount of storage space with respect to a current amount of storage space allocated to each rank until the current amount of storage space used by each respective rank is equal to the predetermined percentage of the predetermined amount of storage space. The destage storage tracks are declined from being destaged from each rank that includes less than or equal to the predetermined percentage of the predetermined amount of storage space rank.

Abstract: A scalable, performance-based, volume allocation technique that can be applied in large storage controller collections is disclosed. A global resource tree of multiple nodes representing interconnected components of a storage system is analyzed to yield gap values for each node for a specific time period. The gap value for each node is an estimate of the amount of the additional or increased workload that can be allocated in the subtree of that node without exceeding the performance and space bounds at any of the nodes in that subtree for the specific time period. The gap values of the global resource tree are further analyzed to generate an ordered allocation list of the volumes of the storage system.

Abstract: In one aspect of the present description, at least one of the value of a prestage trigger and the value of the prestage amount, may be modified as a function of the drive speed of the storage drive from which the units of read data are prestaged into a cache memory. Thus, cache prestaging operations in accordance with another aspect of the present description may take into account storage devices of varying speeds and bandwidths for purposes of modifying a prestage trigger and the prestage amount. Other features and aspects may be realized, depending upon the particular application.

Abstract: A set of logical extents, each having compressed logical tracks of data, is mapped to a head physical extent and, if the head physical extent is determined to have been filled, to at least one overflow extent having spatial proximity to the head physical extent. Pursuant to at least one subsequent write operation and destage operation, the at least one subsequent write operation and destage operation determined to be associated with the head physical extent, the write operation is mapped to one of the head physical extent, the at least one overflow extent, and an additional extent having spatial proximity to the at least one overflow extent.

Abstract: Provided a computer program product, system, and method for cache management of tracks in a first cache and a second cache for a storage. The first cache maintains modified and unmodified tracks in the storage subject to Input/Output (I/O) requests. Modified and unmodified tracks are demoted from the first cache. The modified and the unmodified tracks demoted from the first cache are promoted to the second cache. The unmodified tracks demoted from the second cache are discarded. The modified tracks in the second cache that are at proximate physical locations on the storage device are grouped and the grouped modified tracks are destaged from the second cache to the storage device.

Abstract: Provided are a computer program product, system, and method for using an attribute of a write request to determine where to cache data in a storage system having multiple caches including non-volatile storage cache in a sequential access storage device. Received modified tracks are cached in the non-volatile storage device integrated with the sequential access storage device in response to determining to cache the modified tracks. A write request having modified tracks is received. A determination is made as to whether an attribute of the received write request satisfies a condition. The received modified tracks for the write request are cached in the non-volatile storage device in response to determining that the determined attribute does not satisfy the condition. A destage request is added to a request queue for the received write request having the determined attribute not satisfying the condition.

Abstract: Provided are a computer program product, system, and method for prefetching data tracks and parity data to use for destaging updated tracks. A write request is received including at least one updated track to the group of tracks. The at least one updated track is stored in a first cache device. A prefetch request is sent to the at least one sequential access storage device to prefetch tracks in the group of tracks to a second cache device. A read request is generated to read the prefetch tracks following the sending of the prefetch request. The read prefetch tracks returned to the read request from the second cache device are stored in the first cache device. New parity data is calculated from the at least one updated track and the read prefetch tracks.