International Business Machines Corporation

Kelly B Pushong

Jeffrey Mark Nick

David Harold Surman

Michael J Jordan

Georgette L Kurdt

David Arlen Elko

Steven N Goss

Michael D Swanson

Ruth A Allen

Steven Bruce Jones

Deborah Elizabeth Neuhard

Mark A Brooks

Lisa M Goetze

Inderpal Singh Narang

James Zu-Chia Teng

James C Kleewein

Jeffrey William Josten

Catherine Mary Moxey

Jaime F Anaya

Ronald Elliott Parrish

William Charles Neiman

Dennis J Dahlen

Douglas W Westcott

Gary M King

Kenneth Glenn Rothwell

Joseph S Insalaco

Roger L Brockmeyer

Michael Burrill Phillips

Roger L Brookmeyer

A coupling facility is coupled to one or more other coupling facilities via one or more peer links. The coupling of the facilities enables various functions to be supported, including the duplexing of structures of the coupling facilities. Duplexing is performed on a structure basis, and thus, a coupling facility may include duplexed structures, as well as non-duplexed or simplexed structures.

Controlling the state of duplexing of coupling facility structures

Heuristics are employed to dynamically determine whether a given request is to be driven synchronously or asynchronously. The average synchronous service time associated with previously processed requests is monitored and used, in real-time, along with other information, to determine whether the given request is to be driven synchronously or asynchronously.

Dynamically determining whether to process requests synchronously or asynchronously

Managing the state of coupling facility structures, detecting by one or more systems coupled to the coupling facility, the suspended state of the duplexed command, detecting being independent of message exchange

System-managed duplexing of coupling facility structures. A plurality of instances of coupling facility structures are maintained in a plurality of coupling facilities. Duplexing processing associated with the plurality of instances is managed by one or more operating systems, making many of the steps associated with duplexing transparent to the exploiters of the coupling facility structures. System-managed duplexing provides high availability for coupling facility structure data via a robust recovery mechanism (i.e., duplexing failover).

Managing processing associated with coupling facility Structures

System-managed duplexing of coupling facility structures

Synchronizing processing of commands invoked against duplexed coupling facility structures

Coupling facility store-in cache structures are duplexed in order to improve data availability. That is, once duplexing is established, selective data is written to both a primary structure instance and a secondary structure instance. Thus, if one of the structure instances fails, then the other structure instance is used in order to prevent data from being lost. Duplexing can be started manually and/or automatically by the operating system. Further, a structure may be removed from duplex mode and enter simplex mode, if duplexing is not desired.

Method, system and program products for providing user-managed duplexing of coupling facility cache structures

Castout processing for duplexed data structures. A selective data item is written from a primary instance of a data structure to at least one storage medium. A determination is made as to whether the selective data item can be deleted from a secondary instance of the data structure. If the selective data item can be deleted, it is deleted from the secondary instance.

Castout processing for duplexed cache structures

Rebuilding of storage structures within a shared storage processor of a computing environment. A rebuild of a storage structure, which is owned by an exploiter of the storage structure, is initiated. Thereafter, the storage structure is rebuilt via an operating system of the computing environment. The operating system is distinct from the exploiter owning the storage structure and lacks knowledge of the contents of the storage structure.

System-managed rebuild of coupling facility structures

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Kelly B Pushong