Patents by Inventor Lokesh Mohan Gupta
Lokesh Mohan Gupta has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
-
Patent number: 8095738Abstract: A method for allocating space in a cache based on media I/O speed is disclosed herein. In certain embodiments, such a method may include storing, in a read cache, cache entries associated with faster-responding storage devices and cache entries associated with slower-responding storage devices. The method may further include implementing an eviction policy in the read cache. This eviction policy may include demoting, from the read cache, the cache entries of faster-responding storage devices faster than the cache entries of slower-responding storage devices, all other variables being equal. In certain embodiments, the eviction policy may further include demoting, from the read cache, cache entries having a lower read-hit ratio faster than cache entries having a higher read-hit ratio, all other variables being equal. A corresponding computer program product and apparatus are also disclosed and claimed herein.Type: GrantFiled: June 15, 2009Date of Patent: January 10, 2012Assignee: International Business Machines CorporationInventors: Michael Thomas Benhase, Lawrence Yiumchee Chiu, Lokesh Mohan Gupta, Yu-Cheng Hsu
-
Patent number: 7975169Abstract: 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.Type: GrantFiled: June 3, 2008Date of Patent: July 5, 2011Assignee: International Business Machines CorporationInventors: Kevin John Ash, Michael Thomas Benhase, Lokesh Mohan Gupta, Alfred Emilio Sanchez, Kenneth Wayne Todd
-
Patent number: 7930588Abstract: 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.Type: GrantFiled: January 28, 2009Date of Patent: April 19, 2011Assignee: International Business Machines CorporationInventors: Lawrence Carter Blount, Lokesh Mohan Gupta, Carol Santich Melgren, Kenneth Wayne Todd
-
Patent number: 7895465Abstract: 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.Type: GrantFiled: June 3, 2008Date of Patent: February 22, 2011Assignee: International Business Machines CorporationInventors: Kevin John Ash, Michael Thomas Benhase, Lokesh Mohan Gupta, Alfred Emilio Sanchez, Kenneth Wayne Todd
-
Publication number: 20100191925Abstract: 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.Type: ApplicationFiled: January 28, 2009Publication date: July 29, 2010Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Lawrence Carter BLOUNT, Lokesh Mohan GUPTA, Carol Santich MELLGREN, Kenneth Wayne TODD
-
Patent number: 7761680Abstract: 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.Type: GrantFiled: April 3, 2007Date of Patent: July 20, 2010Assignee: International Business Machines CorporationInventors: Kevin John Ash, Lokesh Mohan Gupta, Steven Robert Lowe, Alfred Emilio Sanchez, Kenneth Wayne Todd
-
Patent number: 7680982Abstract: 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.Type: GrantFiled: February 20, 2007Date of Patent: March 16, 2010Assignee: International Business Machines CorporationInventors: Kevin John Ash, Lokesh Mohan Gupta, Steven Robert Lowe, Alfred Emilio Sanchez, Kenneth Wayne Todd
-
Publication number: 20100037226Abstract: 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.Type: ApplicationFiled: August 11, 2008Publication date: February 11, 2010Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Michael Thomas BENHASE, Susan Kay CANDELARIA, Lokesh Mohan Gupta, Kenneth Wayne Todd
-
Publication number: 20090300408Abstract: 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.Type: ApplicationFiled: June 3, 2008Publication date: December 3, 2009Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Kevin John Ash, Michael Thomas Benhase, Lokesh Mohan Gupta, Alfred Emilio Sanchez, Kenneth Wayne Todd
-
Publication number: 20090300298Abstract: 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.Type: ApplicationFiled: June 3, 2008Publication date: December 3, 2009Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Kevin John Ash, Michael Thomas Benhase, Lokesh Mohan Gupta, Alfred Emilio Sanchez, Kenneth Wayne Todd
-
Patent number: 7562163Abstract: A method is disclosed to locate a data storage device disposed in a data storage system. The method selects a target data storage device, identifies a target adapter port in communication with the target data storage device, and determines one or more target addresses, and determines one or more target World Wide Port Names (“WWPNs”). The method selects an enclosure, and a communication pathway disposed in that enclosure, and determines if any storage device ports interconnected with the communication pathway comprise a WWPN that matches any of said target WWPNs. If any storage device ports interconnected with the communication pathway comprise a WWPN that matches any of the target WWPNs, the method then identifies an adapter port in communication with that communication pathway, and determines if that any storage device ports in communication with the identified adapter port have claimed an address that matches a target address.Type: GrantFiled: August 18, 2006Date of Patent: July 14, 2009Assignee: International Business Machines CorporationInventors: Paul Nicholas Cashman, Lokesh Mohan Gupta, Michael John Jones, Kenney Nian Gan Giu
-
Publication number: 20080250210Abstract: 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.Type: ApplicationFiled: April 3, 2007Publication date: October 9, 2008Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Kevin John Ash, Lokesh Mohan Gupta, Steven Robert Lowe, Alfred Emilio Sanchez, Kenneth Wayne Todd
-
Publication number: 20080201523Abstract: 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.Type: ApplicationFiled: February 20, 2007Publication date: August 21, 2008Inventors: KEVIN JOHN ASH, LOKESH MOHAN GUPTA, STEVEN ROBERT LOWE, ALFRED EMILIO SANCHEZ, KENNETH WAYNE TODD
-
Publication number: 20080126626Abstract: A method is disclosed to locate a data storage device disposed in a data storage system. The method selects a target data storage device, identifies a target adapter port in communication with the target data storage device, and determines one or more target addresses, and determines one or more target World Wide Port Names (“WWPNs”). The method selects an enclosure, and a communication pathway disposed in that enclosure, and determines if any storage device ports interconnected with the communication pathway comprise a WWPN that matches any of said target WWPNs. If any storage device ports interconnected with the communication pathway comprise a WWPN that matches any of the target WWPNs, the method then identifies an adapter port in communication with that communication pathway, and determines if that any storage device ports in communication with the identified adapter port have claimed an address that matches a target address.Type: ApplicationFiled: August 18, 2006Publication date: May 29, 2008Applicant: INTERNATIONAL BUSINESS MACHINES CORPORATIONInventors: Paul Nicholas Cashman, Lokesh Mohan Gupta, Michael John Jones, Kenny Nian Gan Qiu