Abstract: Modified tracks for write requests to a sequential access storage medium in a sequential access storage device are cached in a non-volatile storage, which is a faster access device than the sequential access storage medium. A request queue includes destage requests to destage the modified tracks in the non-volatile storage device to the sequential access storage medium and read requests to access read requested tracks from the sequential access storage medium. A comparison is made of a current position of a read/write mechanism with respect to physical locations on the sequential access storage medium of the tracks subject to the destage requests indicated in the request queue. A determination is made of one of the destage requests to process based on the comparison. The modified track for the determined destage request is written from the non-volatile storage device to the sequential access storage medium.

Abstract: Provided are a computer program product, system, and method for assigning device adaptors and background tasks to use to copy source extents to target extents in a copy relationship. A relation is provided of a plurality of source extents in source ranks to copy to a plurality of target extents in target ranks in the storage system. One target rank in the relation is used to determine an order in which the target ranks in the relation are selected to register for copying. For each selected target rank in the relation selected according to the determined order, an iteration of a registration operation is performed to register the selected target rank and a selected source rank copied to the selected target rank in the relation.

Abstract: The population of data to be inserted into secondary data storage cache is controlled by determining a heat metric of candidate data; adjusting a heat metric threshold; rejecting candidate data provided to the secondary data storage cache whose heat metric is less than the threshold; and admitting candidate data whose heat metric is equal to or greater than the heat metric threshold. The adjustment of the heat metric threshold is determined by comparing a reference metric related to hits of data most recently inserted into the secondary data storage cache, to a reference metric related to hits of data most recently evicted from the secondary data storage cache; if the most recently inserted reference metric is greater than the most recently evicted reference metric, decrementing the threshold; and if the most recently inserted reference metric is less than the most recently evicted reference metric, incrementing the threshold.

Abstract: The population of data to be inserted into secondary data storage cache is controlled by determining a heat metric of candidate data; adjusting a heat metric threshold; rejecting candidate data provided to the secondary data storage cache whose heat metric is less than the threshold; and admitting candidate data whose heat metric is equal to or greater than the heat metric threshold. The adjustment of the heat metric threshold is determined by comparing a reference metric related to hits of data most recently inserted into the secondary data storage cache, to a reference metric related to hits of data most recently evicted from the secondary data storage cache; if the most recently inserted reference metric is greater than the most recently evicted reference metric, decrementing the threshold; and if the most recently inserted reference metric is less than the most recently evicted reference metric, incrementing the threshold.

Abstract: Provided are a computer program product, system, and method for managing data in a cache system comprising a first cache, a second cache, and a storage system. A determination is made of tracks stored in the storage system to demote from the first cache. A first stride is formed including the determined tracks to demote. A determination is made of a second stride in the second cache in which to include the tracks in the first stride. The tracks from the first stride are added to the second stride in the second cache. A determination is made of tracks in strides in the second cache to demote from the second cache. The determined tracks to demote from the second cache are demoted.

Abstract: For efficient task scheduling using a locking mechanism, a new task is allowed to spin on the locking mechanism if a number of tasks spinning on the locking mechanism is less than a predetermined threshold for parallel operations requiring locks between the multiple threads.

Abstract: Provided are a computer program product, system, and method for managing data in a cache system comprising a first cache, a second cache, and a storage system. A determination is made of tracks stored in the storage system to demote from the first cache. A first stride is formed including the determined tracks to demote. A determination is made of a second stride in the second cache in which to include the tracks in the first stride. The tracks from the first stride are added to the second stride in the second cache. A determination is made of tracks in strides in the second cache to demote from the second cache. The determined tracks to demote from the second cache are demoted.

Abstract: Provided are a computer program product, system, and method for managing caching of extents of tracks in a first cache, second cache and storage device. A determination is made of an eligible track in a first cache eligible for demotion to a second cache, wherein the tracks are stored in extents configured in a storage device, wherein each extent is comprised of a plurality of tracks. A determination is made of an extent including the eligible track and whether second cache caching for the determined extent is enabled or disabled. The eligible track is demoted from the first cache to the second cache in response to determining that the second cache caching for the determined extent is enabled. Selection is made not to demote the eligible track in response to determining that the second cache caching for the determined extent is disabled.

Abstract: Data that is to be written is received, wherein the data is indicated in one or more blocks of a first block size. Each of the one or more blocks of the first block size is written in consecutive blocks of a second block size that is larger in size than the first block size, wherein each of the consecutive blocks of the second block size stores only one block of the first block size, and wherein each of the consecutive blocks of the second block size has empty space remaining, subsequent to the writing of each of the one or more blocks of the first block size. Filler data is written in the empty space remaining in each of the consecutive blocks of the second block size.

Abstract: For thresholding task control blocks (TCBs) for staging and destaging, a first tier of TCBs are reserved for guaranteeing a minimum number of TCBs for staging and destaging for storage ranks An additional number of requested TCBs are apportioned from a second tier of TCBs to each of the storage ranks based on a scaling factor that is calculated at predefined time intervals.

Abstract: A point-in-time copy relationship associates tracks in a source storage with tracks in a target storage. The target storage stores the tracks in the source storage as of a point-in-time. A point-in-time copy relationship associates tracks in the source storage with tracks in the target storage, wherein the target storage stores the tracks in the source storage as of a point-in-time. A write request is received including an updated source track for a point-in-time source track in the source storage in the point-in-time copy relationship, wherein the point-in-time source track was in the source storage at the point-in-time the copy relationship was established. The updated source track is stored in a cache device. A prefetch request is sent to the source storage to prefetch the point-in-time source track in the source storage subject to the write request before destaging the updated source track to the source storage.

Abstract: Data that is to be written is received, wherein the data is indicated in one or more blocks of a first block size. Each of the one or more blocks of the first block size is written in consecutive blocks of a second block size that is larger in size than the first block size, wherein each of the consecutive blocks of the second block size stores only one block of the first block size, and wherein each of the consecutive blocks of the second block size has empty space remaining, subsequent to the writing of each of the one or more blocks of the first block size. Filler data is written in the empty space remaining in each of the consecutive blocks of the second block size.

Abstract: A plurality of tracks is examined for meeting criteria for a discard scan. In lieu of waiting for a completion of a track access operation, at least one of the plurality of tracks is marked for demotion. An additional discard scan may be subsequently performed for tracks not previously demoted. The discard and additional discard scans may proceed in two phases.

Abstract: A mechanism is provided in a data processing system. The mechanism determines a maximum queue depth of a queue for each solid state drive in a plurality of solid state drives. A given data block is mirrored between a group of solid state drives within the plurality of solid state drives. The mechanism tracks outstanding input/output operations in a queue for each of the plurality of solid state drives. For a given read operation to read the given data block, the mechanism identifies a solid state drive within the group of solid state drives based on a number of empty slots in the queue of each solid state drive within the group of solid state drives.

Abstract: For efficient track destage in secondary storage in a more effective manner, for temporal bits employed with sequential bits for controlling the timing for destaging the track in a primary storage, the temporal bits and sequential bits are transferred from the primary storage to the secondary storage. The temporal bits are allowed to age on the secondary storage.

Abstract: Provided are a computer program product, system, and method for managing caching of extents of tracks in a first cache, second cache and storage device. A determination is made of an eligible track in a first cache eligible for demotion to a second cache, wherein the tracks are stored in extents configured in a storage device, wherein each extent is comprised of a plurality of tracks. A determination is made of an extent including the eligible track and whether second cache caching for the determined extent is enabled or disabled. The eligible track is demoted from the first cache to the second cache in response to determining that the second cache caching for the determined extent is enabled. Selection is made not to demote the eligible track in response to determining that the second cache caching for the determined extent is disabled.

Abstract: Provided are a computer program product, system, and method for managing caching of extents of tracks in a first cache, second cache and storage device. A determination is made of an eligible track in a first cache eligible for demotion to a second cache, wherein the tracks are stored in extents configured in a storage device, wherein each extent is comprised of a plurality of tracks. A determination is made of an extent including the eligible track and whether second cache caching for the determined extent is enabled or disabled. The eligible track is demoted from the first cache to the second cache in response to determining that the second cache caching for the determined extent is enabled. Selection is made not to demote the eligible track in response to determining that the second cache caching for the determined extent is disabled.

Abstract: Provided are a computer program product, system, and method for managing data in a first cache and a second cache. A reference count is maintained in the second cache for the page when the page is stored in the second cache. It is determined that the page is to be promoted from the second cache to the first cache. In response to determining that the reference count is greater than zero, the page is added to a Least Recently Used (LRU) end of an LRU list in the first cache. In response to determining that the reference count is less than or equal to zero, the page is added to a Most Recently Used (LRU) end of the LRU list in the first cache.

Abstract: Provided are a computer program product, system, and method for managing data in a first cache and a second cache. A reference count is maintained in the second cache for the page when the page is stored in the second cache. It is determined that the page is to be promoted from the second cache to the first cache. In response to determining that the reference count is greater than zero, the page is added to a Least Recently Used (LRU) end of an LRU list in the first cache. In response to determining that the reference count is less than or equal to zero, the page is added to a Most Recently Used (LRU) end of the LRU list in the first cache.

Abstract: Embodiments of the disclosure relate to archiving data in a storage system. An exemplary embodiment comprises making a flash copy of data in a source volume, compressing data in the flash copy wherein each track of data is compressed into a set of data pages, and storing the compressed data pages in a target volume. Data extents for the target volume may be allocated from a pool of compressed data extents. After each stride worth of data is compressed and stored in the target volume, data may be destaged to avoid destage penalties. Data from the target volume may be decompressed from a flash copy of the target volume in a reverse process to restore each data track, when the archived data is needed. Data may be compressed and uncompressed using a Lempel-Ziv-Welch process.