Patent application number | Description | Published |
20080201523 | PRESERVATION OF CACHE DATA FOLLOWING FAILOVER - In a data storage subsystem with disk storage and a pair of clusters, one set of DASD fast write data is in cache of one cluster and in non-volatile data storage of the other. In response to a failover of one of the pair of clusters to a local cluster, the local cluster converts the DASD fast write data in local cache to converted fast write data to prioritize the converted data for destaging to disk storage. In response to failure to destage, the local cluster allocates local non-volatile storage tracks and emulates a host adapter to store the converted fast write data by the local non-volatile storage, reconverting the converted fast write data of the non-volatile storage to local DASD fast write data stored in the local non-volatile storage and stored in the local cache storage. | 08-21-2008 |
20080250210 | COPYING DATA FROM A FIRST CLUSTER TO A SECOND CLUSTER TO REASSIGN STORAGE AREAS FROM THE FIRST CLUSTER TO THE SECOND CLUSTER - Provided are a method, system, and article of manufacture for copying data from a first cluster to a second cluster to reassign storage areas from the first cluster to the second cluster. An operation is initiated to reassign storage areas from a first cluster to a second cluster, wherein the first cluster includes a first cache and a first storage unit and the second cluster includes a second cache and a second storage unit. Data in the first cache for the storage areas to reassign to the second cluster is copied to the second cache. Data in the first storage unit for storage areas remaining assigned to the first cluster is copied to the second storage unit. | 10-09-2008 |
20090300298 | MEMORY PRESERVED CACHE TO PREVENT DATA LOSS - A method, system, and computer program product for preserving data in a storage subsystem having dual cache and dual nonvolatile storage (NVS) through a failover from a failed cluster to a surviving cluster is provided. A memory preserved indicator is initiated to mark tracks on a cache of the surviving cluster to be preserved, the tracks having an image in an NVS of the failed cluster. A destage operation is performed to destage the marked tracks. Subsequent to a determination that each of the marked tracks have been destaged, the memory preserved indicator is disabled to remove the mark from the tracks. If the surviving cluster reboots previous to each of the marked tracks having been destaged, the cache is verified as a memory preserved cache, the marked tracks are retained for processing while all unmarked tracks are removed, and the marked tracks are processed. | 12-03-2009 |
20090300408 | MEMORY PRESERVED CACHE FAILSAFE REBOOT MECHANISM - A method, system and computer program product for preserving data in a storage subsystem having dual cache and dual nonvolatile storage (NVS) through a failover from a failed cluster to a surviving cluster, the surviving cluster undergoing a rebooting process, is provided. A memory preserved indicator associated with a cache of the surviving cluster is detected. The memory preserved indicator designates marked tracks having an image in an NVS of the failed cluster to be preserved through the rebooting process. A counter in a data structure of the surviving cache is incremented. If a value of the counter exceeds a predetermined value, a cache memory is initialized, and the marked tracks are removed from the cache to prevent an instance of repetitive reboots caused by a corrupted structure in the cache memory. | 12-03-2009 |
20100037226 | GROUPING AND DISPATCHING SCANS IN CACHE - A method, system, and computer program product for grouping and dispatching scans in a cache directory of a processing environment is provided. A plurality of scan tasks is aggregated from a scan wait queue into a scan task queue. The plurality of scan tasks is determined by selecting one of (1) each of the plurality of scan tasks on the scan wait queue, (2) a predetermined number of the plurality of scan tasks on the scan wait queue, and (3) a set of scan tasks of a similar type on the scan wait queue. A first scan task from the plurality of scan tasks is selected from the scan task queue. The scan task is performed. | 02-11-2010 |
20100191925 | DEFERRED VOLUME METADATA INVALIDATION - A method, system, and computer program product for managing modified metadata in a storage controller cache pursuant to a recovery action by a processor in communication with a memory device is provided. A count of modified metadata tracks for a storage rank is compared against a predetermined criterion. If the predetermined criterion is met, a storage volume having the storage rank is designated with a metadata invalidation flag to defer metadata invalidation of the modified metadata tracks until after the recovery action is performed. | 07-29-2010 |
20120131293 | DATA ARCHIVING USING DATA COMPRESSION OF A FLASH COPY - 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. | 05-24-2012 |
20130212347 | MULTI-TARGET, POINT-IN-TIME-COPY ARCHITECTURE WITH DATA DEDUPLICATION - A method for performing a write to a source volume in a multi-target architecture is described. The multi-target architecture includes a source volume and multiple target volumes mapped thereto. In one embodiment, such a method includes copying data in a track of the source volume to a corresponding track of a target volume (target x). The method enables one or more sibling target volumes (siblings) mapped to the source volume to inherit the data from the target x. When the data is successfully copied to the target x, the method performs a write to the track of the source volume. Other methods for reading and writing data to volumes in the multi-target architecture are also described. | 08-15-2013 |
20130219122 | MULTI-STAGE CACHE DIRECTORY AND VARIABLE CACHE-LINE SIZE FOR TIERED STORAGE ARCHITECTURES - A method in accordance with the invention includes providing first, second, and third storage tiers, wherein the first storage tier acts as a cache for the second storage tier, and the second storage tier acts as a cache for the third storage tier. The first storage tier uses a first cache line size corresponding to an extent size of the second storage tier. The second storage tier uses a second cache line size corresponding to an extent size of the third storage tier. The second cache line size is significantly larger than the first cache line size. The method further maintains, in the first storage tier, a first cache directory indicating which extents from the second storage tier are cached in the first storage tier, and a second cache directory indicating which extents from the third storage tier are cached in the second storage tier. | 08-22-2013 |
20130219141 | CASCADED, POINT-IN-TIME-COPY ARCHITECTURE WITH DATA DEDUPLICATION - A method for performing a write to a volume x in a cascaded architecture is described. In one embodiment, such a method includes determining whether the volume x has a child volume, wherein each of the volume x and the child volume have a target bit map (TBM) associated therewith. The method then determines whether the TBMs of both the volume x and the child volume are set. If the TBMs are set, the method finds a higher source (HS) volume from which to copy the desired data to the child volume. Finding the HS volume includes travelling up the cascaded architecture until the source of the data is found. Once the HS volume is found, the method copies the data from the HS volume to the child volume and performs the write to the volume x. A method for performing a read is also disclosed herein. | 08-22-2013 |
20130219142 | DELETING RELATIONS IN MULTI-TARGET, POINT-IN-TIME-COPY ARCHITECTURES WITH DATA DEDUPLICATION - A method for deleting a relation between a source and a target in a multi-target architecture is described. The multi-target architecture includes a source and multiple targets mapped thereto. In one embodiment, such a method includes initially identifying a relation for deletion from the multi-target architecture. A target associated with the relation is then identified. The method then identifies a sibling target that inherits data from the target. Once the target and the sibling target are identified, the method copies the data from the target to the sibling target. The relation between the source and the target is then deleted. A corresponding computer program product is also disclosed and claimed herein. | 08-22-2013 |
20140082231 | EFFICIENT PROCESSING OF CACHE SEGMENT WAITERS - For a plurality of input/output (I/O) operations waiting to assemble complete data tracks from data segments, a process, separate from a process responsible for the data assembly into the complete data tracks, is initiated for waking a predetermined number of the waiting I/O operations. A total number of I/O operations to be awoken at each of an iterated instance of the waking is limited. | 03-20-2014 |
20140082254 | RECOVERY FROM CACHE AND NVS OUT OF SYNC - For cache/data management in a computing storage environment, incoming data segments into a Non Volatile Storage (NVS) device of the computing storage environment are validated against a bitmap to determine if the incoming data segments are currently in use. Those of the incoming data segments determined to be currently in use are designated to the computing storage environment to protect data integrity. | 03-20-2014 |
20140082292 | EFFICIENT CACHE VOLUME SIT SCANS - A processor, operable in a computing storage environment, allocates portions of a Scatter Index Table (SIT) disproportionately between a larger portion dedicated for meta data tracks, and a smaller portion dedicated for user data tracks, and processes a storage operation through the disproportionately allocated portions of the SIT using an allocated number of Task Control Blocks (TCB). | 03-20-2014 |
20140082296 | DEFERRED RE-MRU OPERATIONS TO REDUCE LOCK CONTENTION - Data operations, requiring a lock, are batched into a set of operations to be performed on a per-core basis. A global lock for the set of operations is periodically acquired, the set of operations is performed, and the global lock is freed so as to avoid excessive duty cycling of lock and unlock operations in the computing storage environment. | 03-20-2014 |
20140082629 | PREFERENTIAL CPU UTILIZATION FOR TASKS - A set of like tasks to be performed is organized into a first group. Upon a determined imbalance between dispatch queue depths greater than a predetermined threshold, the set of like tasks is reassigned to an additional group. | 03-20-2014 |