International Business Machines Corporation

Vernon John Legvold

Matthew John Fairhurst

Michael P Vageline

Michael John Jones

Susan Kay Candelaria

Michael Howard Hartung

Ronald David Martens

Steven Douglas Johnson

Edward George Butt

Joel H Cord

Jack Harvey Derenburger

Carol Santich Michod

William Frank Micka

Brent Cameron Beardsley

Warren Keith Stanley

Yu-Cheng Hsu

Joseph S Hyde, Ii

Lawrence Carter Blount

David Frank Mannenbach

Chan Y Ng

William G Sherman, Ii

Kevin J Ash

Carol Santich Mellgren

Kenneth Wayne Todd

John Richard Paveza

Yoram Novick

John Norbert McCauley

Mark Albert Reid

Pnina A Vortman

Gary Eugene Morain

Steven Robert Lowe

James Lincoln Iskiyan

Stephen C West

Lloyd R Shipman, Jr

Kenneth M Nagin

William Dennis Williams

Jeffrey R Steffan

Joseph Smith Hyde

Peter L Leung

Steven Richard Van Gundy

Julia Liu

Kenneth Wayne Lane

Dennis Albert Kukula

Elfraim Zeidner

Guy Eugene Martin

William Lee Richardson

Stephen O Wellons

Guy E Martin

Emeline Yvonne Germain

Provided is a method, system, and program for processing Input/Output (I/O) requests to a storage network including at least one storage device and at least two adaptors, wherein each adaptor is capable of communicating I/O requests to the at least one storage device. An error is detected in a system including a first adaptor, wherein the first adaptor is capable of communicating on the network after the error is detected. In response to detecting the error, a master switch timer is started that is less than a system timeout period if the first adaptor is the master. An error recovery procedure in the system including the first adaptor would be initiated after the system timeout period has expired. An operation is initiated to designate another adaptor in the storage network as the master if the first adaptor is the master in response to detecting an expiration of the master switch timer.

System and program for error handling in a dual adaptor system where one adaptor is a master

Method, system, and program for error handling in a dual adaptor system where one adaptor is a master

Provided is a system for processing Input/Output (I/O) requests to a storage network including at least one storage device and at least two adaptors, wherein each adaptor is capable of communicating I/O requests to the at least one storage device. An error is detected in a system including a first adaptor, wherein the first adaptor is capable of communicating on the network after the error is detected. In response to detecting the error, a master switch timer is started that is less than a system timeout period if the first adaptor is the master. An error recovery procedure in the system including the first adaptor would be initiated after the system timeout period has expired. An operation is initiated to designate another adaptor in the storage network as the master if the first adaptor is the master in response to detecting an expiration of the master switch timer.

System for error handling in a dual adaptor system where one adaptor is a master

A system, method and article of manufacture are provided for the automatic recovery from errors encountered during an automated Licensed Internal Code (LIC) update on a storage controller. The present invention functions with a concurrent or nonconcurrent automated LIC update. The automated recovery from many error conditions is transparent to the attached host system and on-site service personnel, resulting an improvement in the LIC update process.

Automated error recovery of a licensed internal code update on a storage controller

Provided is a method for processing Input/Output (I/O) requests to a storage network including at least one storage device and at least two adaptors, wherein each adaptor is capable of communicating I/O requests to the at least one storage device. An error is detected in a system including a first adaptor, wherein the first adaptor is capable of communicating on the network after the error is detected. In response to detecting the error, a master switch timer is started that is less than a system timeout period if the first adaptor is the master. An error recovery procedure in the system including the first adaptor would be initiated after the system timeout period has expired. An operation is initiated to designate another adaptor in the storage network as the master if the first adaptor is the master in response to detecting an expiration of the master switch timer.

Method for error handling in a dual adaptor system where one adaptor is a master

A system, method and article of manufacture are provided for the automatic recovery from errors encountered during an automated Licensed Internal Code (LIC) update on a storage controller. The present invention functions with a concurrent or nonconcurrent automated LIC update. The automated recovery from many error conditions is transparent to the attached host system and on-site service personnel, resulting in an improvement in the LIC update process.

A system, method and article of manufacture are provided to perform an automated concurrent licensed internal code (LIC) update and an automated nonconcurrent LIC update on a storage controller. The automated concurrent LIC update is performed on a storage controller by sequentially updating each cluster while maintaining operation of the storage controller. The automated concurrent LIC update allows multiple hosts to continue to access data via the storage controller while the system is actively undergoing the LIC update. The automated nonconcurrent LIC update is performed during the time the storage controller in not operating. The automated nonconcurrent LIC update allows service personnel to perform the update in an efficient and timely manner. When the update has completed, the storage controller becomes available to process data and the system is operating at the latest LIC level.

Automated control of a licensed internal code update on a storage controller

A dual cluster storage server maintains track control blocks (TCBs) in a data structure to describe the data stored in cache in corresponding track images or segments. Following a cluster failure and reboot, the surviving cluster uses the TCBs to rebuild data structures such as a scatter table, which is a hash table that identifies a location of a track image, and a least recently used (LRU)/most recently used (MRU) list for the track images. This allows the cache data to be recovered. The TCBs describe whether the data in the track images is modified and valid, and describe forward and backward pointers for the data in the LRU/MRU lists. A separate non-volatile memory that is updated as the track images are updated is used to verify the integrity of the TCBs.

Preserving cache data against cluster reboot

An improved storage controller and method for storing and recovering data are disclosed. The storage controller includes a first cluster for directing data from a host computer to a storage device and a second cluster for directing data from a host computer to a storage device. A first cache memory is connected to the first cluster and a second cache memory is connected to the second cluster. A first preserved area of memory is connected to the first cluster and a second preserved area of memory is connected to the second cluster. Data is directed to the first cache and backed up to the second preserved area in a normal operating mode. Similarly, data is directed to the second cache and backed up to the first preserved area in the normal operating mode. In the event of a power failure or comparable event, data from the first and second preserved areas are transferred to, and stored on, a first storage device. Additionally, data from the first and second preserved areas are transferred to, and stored on, a second storage device. Thus, upon resumption of normal operation, if one of the clusters subsequently fails to resume normal operations, data from the failed cluster is available through the operating cluster.

Autonomic power loss recovery for a multi-cluster storage sub-system

Provided are a method, system, and program for maintaining data in a first cache and second cache, wherein a backup cache maintains a backup copy of data in the first cache, and wherein the first cache is used to cache a first set of data in a storage system and the second cache is used to cache a second set of data in the storage system. An unavailable state of the first cache is detected. In response to detecting the unavailable state, requests to the first set of data are blocked and at least one space in the second cache is allocated for data in the backup cache. Requests to the first set of data are allowed to proceed after the at least one space is allocated in the second cache and before the data in the backup cache is copied to the at least one allocated space in the second cache. The data from the backup cache is copied to the allocated at least one space in the second cache after the requests to the first set of data are allowed to proceed.

Method, system, and program for restoring data in cache

Disclosed is a system, method, and program for limiting input/output (I/O) requests from an application program to a storage device to facilitate the processing of data in memory. A determination is made as to whether an amount of a set of data in memory exceeds at least one threshold. At least one of multiple paths to the storage device is indicated as blocked to I/O requests from the application program. Each indicated blocked path is available for processing the set of data in memory. An I/O request from the application program is received and a determination is made as to whether the received I/O request intends to access the storage device using one indicated blocked path. The I/O request is denied access to the storage device via the blocked path.

System, method, and program for managing I/O requests to a storage device

A data storage system provides generalized record caching through a control unit adapted to support track caching in the upper level store of a two level memory. Dynamic reallocation of space between each type of caching in the upper store follows operating patterns of host computer systems using the data storage system. A storage controller cache has a plurality of segments. A directory data entry data structure is allocated each segment. Such allocated directory entries are used to identify tracks as cached. A plurality of unallocated directory entries are also provided. As a record is cached in a segment outside of a track slot, an unallocated directory entry is used to identify a virtual track in cache corresponding to the track of the record in the lower level store. Records from one track can thus appear in several segments outside track slots. Tracking of records to locate records least recently used is done globally over all track slots and record caching segments and locally within individual record caching segments. A mechanism is provided for identifying record slots, as they become least recently used, and dropping them from the upper level store in the face of competing demands for the space. A second mechanism identifies least recently used segments for dropping from the upper level store.

Method and system for dynamic cache allocation between record and track

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Tucson, AZ, United States of America

Vernon John Legvold