International Business Machines Corporation

James M Showalter

Robert Bradley Bennett

Thomas J Szczygielski

Barbara A Maslak

Robert Michael Nugent

Edmond A Pruul

Michael K Ainsworth

Amos S Tanner

Matthew Joseph Anglin

Gregory John Tevis

Kershaw S Mehta

Donald Paul Warren, Jr

Scott Thomas Marcotte

William W Chow

Andrew Coleman

Eugene Johnson

Edward Joseph Bendert

William James Schoen

David A Wise

Renata Rand McFadden

Mary E Vendryes

John Lee Brooks

Cherie C Barnes

Richard L Stone

John A Henry

Geoffrey E Miller

Susan M Kimmel

Mary Ng

A method comprising, sending an instruction from a validator member of a sysplex to a second member of a sysplex to prevent operations that alter a sysplex namespace, determining whether the validator member of the sysplex is communicative with the second member of the sysplex and whether the members of the sysplex retain current sysplex status information, sending an instruction from the validator member to the second member to send a first namespace attribute data associated with the second member to the validator member responsive to determining that the validator member of the sysplex is communicative with the second member of the sysplex and the members of the sysplex retain current sysplex status information, determining whether the first namespace attribute data associated with the second member is consistent with a second namespace attribute data, and sending an instruction to correct the first namespace attribute data.

Validation and correction in a distributed namespace

Application access to locally and remotely exported file systems is coordinated to allow caching data for exported file systems accessed by remote clients. In response to a request or file system access, it is determined whether the request relates to a locally exported file system or a remotely exported file system. If the request relates to a locally exported file system, a local access routine is invoked to obtain access permissions to the locally exported file system. If the request relates to remotely exported file system, a remote access routine is invoked to communicate with a local access routine in a file server responsible for coordinating access to the remotely exported file system to obtain access permissions to the remotely exported file system.

Method, computer program product, and system for coordinating access to locally and remotely exported file systems

A system and method efficiently manage clones of an object group. A base storage area contains metadata for each of multiple objects in the object group. The metadata for each object identifies data within each object. The system receives a request to clone a base storage area, and in response, the system creates a clone storage area containing an identification of the base storage area but not the metadata. If there is a subsequent request to update a portion of one of the objects, then the system copies the portion, copies the metadata into the clone storage area for the one object, makes the update to the object copy and changes the metadata in the base storage area to identify the portion copy instead of the original portion. If there is no subsequent request to update any of the multiplicity of objects, then the system does not copy the metadata for any of the multiplicity of objects into the clone storage area.

Creation of clone storage area with identification of base storage area

A file management and backup system manages access to data objects such as records stored in a primary repository, and occasionally backs-up the data objects to a backup repository. A backup utility within the system, periodically or at the request of a user, makes a backup request to a file manager, and specifies the scope of the backup. In response, the file manager makes an entry in a 'backup in progress' table indicating that the corresponding file space(s), directory(ies), file(s) and/or data object(s) are currently involved in a consistent backup procedure. Then, the backup utility commences the actual copying of the data within the backup scope to the backup repository with assistance from the file manager in accessing the data from the primary repository. If a request is made to update a file space, directory, file or data object within the backup scope once the entry is made in the backup in progress table, the file manager makes a 'shadow' or copy of the file space, directory, file or data object for which update is requested. Then, the file manager updates the original file space, directory, file or data object, and uses the shadow copy for the backup procedure. After the backup is completed, the shadow copy is invalidated. If the update request is made during the backup procedure to a directory, file or data object which has already been backed-up, then a shadow copy is not necessary.

Computer file management and backup system

A method and system for integrating migration level two (ML2) and backup tape processing provide for the backup, archival, and/or restoration of ML2 tape files without the use of tape mounts. In this manner, the amount of data movement required to recover from data loss is significantly reduced. Tape files may be recovered to their original status, even if the file has migrated to ML2. The status of the data is preserved after such a recovery operation. In this manner, data movement is reduced because no remigration of data is required after a recovery.

Integration of migration level two and backup tape processing using

A computer system or network tailors scopes of commit processing by using local work unit identifiers and more global logical unit of work identifiers. The local work unit identifiers are used to identify the scope of commit processing within each execution environment, and the logical unit of work identifiers are used to identify related work units of different execution environments. The related work units are coupled to each other by a protected conversation between the execution environments.

Local and global commit scopes tailored to work units

In a computer system or process, sync point managers are distributed throughout each real machine for a plurality of execution environments, but all of the execution environments and sync point managers within one real machine share a common recovery facility and recovery log. A common recovery log is used by the recovery facility for all of the execution environments in the system. Different systems are interconnected by a communication facility and each has its own recovery facility and recovery log. A protected conversation can be initiated between the first and second execution environments in the same real machine, and the sync point managers within the respective execution environments coordinate the two-phase commit procedures associated with the protected conversations. A conversation manager within each real machine assists in routing the conversation between the first and second execution environments. Each resource manager, whether residing inside or outside of the real machine, has its own recovery log, but uses the recovery facility of the real machine that accesses the resource.

Coordinated sync point management of protected resources

To recover a failed commit procedure, a first recovery facility collects and compares sync point state information from a variety of different types of resources including a data repository and a protected conversation. The comparison of the sync point state information is made automatically in response to a sync point failure event. A second recovery facility serving another execution environment notifies the first recovery facility after a failure and subsequent recovery procedure of the second execution environment has completed. The first recovery facility makes automatic cyclic attempts to communicate with the second recovery facility. The first recovery facility can receive a manually initiated but automatically simulated response of sync point state information when there is a failure such that actual sync point state information cannot be received. The first recovery facility is responsive to the simulated sync point state information to proceed with a recovery operation substantially as if actual sync point state information were received.

Recovery facility for incomplete sync points for distributed application

A computer system provides registration of resource for synchronization point processing. Resources include file systems, data bases, and protected conversations. A resource becomes protected by the system when it is registered in the application's execution environment. The execution environment includes but is not exclusive to the interactive environment. Accordingly the invention provides an efficient and uniform method for identification of protected resources. The registration facility is separate from the application. Thus, the users of applications, application program developers, system administrators and operators need not have to consider or design a registration facility but only involve the one provided. A protected resource manager, through its adapter, can modify, at any time, the registration information, either by adding missing information or by changing the existing information. A resource registers only for the work unit in which it wishes to participate. An application could have several work units. A resource can register for two work units in the application or two resources can register for a single work unit or both.

Registration of resources for commit procedures

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Endicott, NY, United States of America

James M Showalter