Abstract: For a cache in which a plurality of frequently accessed data segments are temporarily stored, reference count information of the plurality of data segments, in conjunction with least recently used (LRU) information, is used to determine a length of time to retain the plurality of data segments in the cache according to a predetermined weight, where notwithstanding the LRU information, those of the plurality of data segments having a higher reference counts are retained longer than those having lower reference counts.

Abstract: Various embodiments for improving hash index key lookup caching performance in a computing environment are provided. In one embodiment, for a cached fingerprint map having a plurality of entries corresponding to a plurality of data fingerprints, reference count information is used to determine a length of time to retain the plurality of entries in cache. Those of the plurality of entries having a higher reference counts are retained longer than those having lower reference counts.

Abstract: An apparatus and method for copying data are disclosed. A data track to be replicated using a peer-to-peer remote copy (PPRC) operation is identified. The data track is encoded in a non-transitory computer readable medium disposed in a first data storage system. At a first time, a determination of whether the data track is stored in a data cache is made. At a second time, the data track is replicated to a non-transitory computer readable medium disposed in a second data storage system. The second time is later than the first time. If the data track was stored in the data cache at the first time, a cache manager is instructed to not demote the data track from the data cache. If the data track was not stored in the data cache at the first time, the cache manager is instructed that the data track may be demoted.

Abstract: Various embodiments for improving data storage and retrieval performance, for a tiered storage environment having levels corresponding to storage performance, are provided. In one embodiment, by way of example only, reference count information of at least one data segment maintained in the tiered storage environment is used to determine which of the levels in the tiered storage environment the at least one data segment will be assigned. Those of the at least one data segment having higher reference counts are assigned to a higher performance level than those having lower reference counts.

Abstract: Various embodiments for improving hash index key lookup caching performance in a computing environment are provided. In one embodiment, for a cached fingerprint map having a plurality of entries corresponding to a plurality of data fingerprints, reference count information is used to determine a length of time to retain the plurality of entries in cache. Those of the plurality of entries having a higher reference counts are retained longer than those having lower reference counts.

Abstract: For a cache in which a plurality of frequently accessed data segments are temporarily stored, reference count information of the plurality of data segments, in conjunction with least recently used (LRU) information, is used to determine a length of time to retain the plurality of data segments in the cache according to a predetermined weight, where notwithstanding the LRU information, those of the plurality of data segments having a higher reference counts are retained longer than those having lower reference counts.

Abstract: Various embodiments for improving data storage and retrieval performance, for a tiered storage environment having levels corresponding to storage performance, are provided. In one embodiment, by way of example only, reference count information of at least one data segment maintained in the tiered storage environment is used to determine which of the levels in the tiered storage environment the at least one data segment is assigned. Those of the at least one data segment having higher reference counts are assigned to a higher performance level than those having lower reference counts.

Abstract: Methods, controllers for data storage, data storage systems, and computer program products are directed to migrating data after the initial placement of the data in data storage entities having higher speed and in other data storage. Steps of a method to migrate data to the higher speed data storage are (1) identifying at least one group of data having had at least one I/O activity in each of a plurality of intervals of time, occurring over a string of multiple intervals of time, wherein the I/O activity is with respect to the other data storage from which data is to be migrated. The time for each of the multiple intervals is selected such that bursts of the I/O activity are likely to be contained in one interval. (2) The identified group of data is classified to the higher speed data storage and migrated.

Abstract: Methods, controllers for data storage, data storage systems, and computer program products are directed to migrating data after the initial placement of the data in data storage entities having higher speed and in other data storage. Steps of a method to migrate data to the higher speed data storage are (1) identifying at least one group of data having had at least one I/O activity in each of a plurality of intervals of time, occurring over a string of multiple intervals of time, wherein the I/O activity is with respect to the other data storage from which data is to be migrated. The time for each of the multiple intervals is selected such that bursts of the I/O activity are likely to be contained in one interval. (2) The identified group of data is classified to the higher speed data storage and migrated.

Abstract: Provided are a method, system, and article of manufacture for using different algorithms to destage different types of data from cache. A first destaging algorithm is used to destage a first type of data to a storage for a first duration. A second destaging algorithm is used to destage a second type of data to the storage for a second duration.

Abstract: Provided are a method, system, and article of manufacture, wherein a request to write data to a storage medium is received. The data requested to be written to the storage medium is stored in a cache. A writing of the data is initiated to the storage medium. A periodic determination is made as to whether the stored data in the cache is the same as the data written to the storage medium.

Abstract: Provided are a method, system and program for using multiple data structures to manage data in cache. A plurality of data structures each have entries identifying data from a first computer readable medium added to a second computer readable medium. A request is received for data in the first computer readable medium. A determination is made as to whether there is an entry for the requested data in one of the data structures. The requested data is retrieved from the first computer readable medium to store in the second computer readable medium in response to determining that there is no entry for the requested data in one of the data structures. One of the data structures is selected in response to determining that there is no entry for the requested data in one of the data structures and an entry for the retrieved data is added to the selected data structure.

Abstract: Provided are a method, system, and article of manufacture, where a plurality of extents are stored in a first set of storage units coupled to a controller. A determination is made that a second set of storage units has been coupled to the controller. The plurality of extents are distributed among all storage units included in the first set of storage units and the second set of storage units.

Abstract: Provided are a method, system, and article of manufacture for using different algorithms to destage different types of data from cache. A first destaging algorithm is used to destage a first type of data to a storage for a first duration. A second destaging algorithm is used to destage a second type of data to the storage for a second duration.

Abstract: Provided are a method, system, and article of manufacture for using different algorithms to destage different types of data from cache. A first destaging algorithm is used to destage a first type of data to a storage for a first duration. A second destaging algorithm is used to destage a second type of data to the storage for a second duration.

Abstract: Provided are a method, system, and article of manufacture for managing write requests in cache directed to different storage groups. A determination is made of a high and low thresholds for a plurality of storage groups configured in a storage, wherein the high and low thresholds for one storage group indicate a high and low percentage of a cache that may be used to store write requests to the storage group. A determination is made of a number of tasks to assign to the storage groups based on the determined high and low thresholds for the storage groups, wherein each task assigned to one storage group destages write requests from the cache to the storage group.

Abstract: A method, apparatus and program storage device for protecting data write operations against write failures in a data storage device is provided. The data storage device includes a storage medium, a write cache including a copy of data written to the storage medium, and a controller configured for testing data write operations to the storage medium. The controller tests data write operations to the storage medium before the write cache is flushed to confirm that it is safe to flush the write cache. If the test fails, the data in the write cache can be recovered.

Abstract: Disclosed is a method, system, and program for managing metadata in cache. A first policy is used to determine when to remove data from a primary cache, and a second policy is used to determine when to remove data from a metadata cache.

Abstract: Provided are a method, system, and program for accessing a resource. Requests are generated to access a resource in a first access mode and a second access mode. The requests are processed to access the resource in the second mode before processing at least one request to access the resource in the first access mode. The processing of the requests to access the resource in the first access mode is delayed for a time period after processing all the requests to access the resource in the second access mode in order to wait to receive a subsequent request to access the resource in the second access mode.

Abstract: Provided are a method, system, and article of manufacture, where a plurality of extents are stored in a first set of storage units coupled to a controller. A determination is made that a second set of storage units has been coupled to the controller. The plurality of extents are distributed among all storage units included in the first set of storage units and the second set of storage units.