International Business Machines Corporation

Tri M Hoang

William J Rooney

Scott Brady Compton

Gregory E McBride

Carol Santich Mellgren

Harry M Yudenfriend

Dale Francis Riedy, Jr

David Randall Blea

Tabor R Powelson

Tariq Hanif

Matthew J Kalos

Clint Alan Hardy

Elpida Tzortzatos

Warren Keith Stanley

Susan Kay Candelaria

John Glenn Thompson

Nicolas Marc Clayton

Lisa Joan Gundy

Matthew Richard Craig

David B Emmes

Danny R Sutherland

William C Shepard

Corey G Smeaton

Mariama Ndoye

Michael J Shannon

Tracy D Butler

Stephen M Kocik

Bengt E Larsson

Data consistent freeze of peer-to-peer remote copy in a multiple computing cluster environment includes freezing, by each of a first computing cluster and a second computing cluster, non-shared logical volumes of the first computing cluster and the second computing cluster; freezing, by each of the first computing cluster and the second computing cluster, shared logical volumes of the first computing cluster and the second computing cluster, wherein a key logical volume is a last shared logical volume to be frozen; selecting one of the first computing cluster and the second computing cluster to perform thaws of the shared logical volumes based on which of the first computing cluster or the second computing cluster was the last to freeze the key logical volume; and thawing, by the selected one of the first computing cluster and the second computing cluster, the shared logical volumes.

Data consistent freeze of peer-to-peer remote copy in a multiple computing cluster environment

A method, computer system, and a computer program product for soft fencing is provided. The present invention may include identifying a logical device swap occurred. The present invention may also include, in response to a logical device swap, creating a soft fence command. The present invention may then include issuing the created soft fence command.

Enhanced soft fence of devices

One general aspect of device reservation management in accordance with the present description, is directed to a host issuing I/O data requests to a primary device which synchronously mirrors data to a secondary data storage device wherein both devices are reserved for exclusive use by the host for I/O data requests. In response to a loss of communication connectivity on all paths to the primary storage controller controlling the primary device, the host confirms whether a communication path to the primary device has been established and whether the primary device remains reserved to the host. Upon successful confirmations, the reservation of the primary device is repaired such that I/O data requests to the reserved primary device continue. Other features and aspects may be realized, depending upon the particular application.

Device reservation management for overcoming communication path disruptions

Aspects include a computer-implemented method for managing alias devices across logical control units. Aspects include establishing one or more alias management groups associated with a set of one or more logical control units. Aspects also include responsive to one or more changes to the set of network paths of a first logical control unit in the set of logical control units performing a method comprising: marking a first alias management group associated with the first logical control unit as invalid for alias borrowing. Then, performing a first synchronized CPU enablement operation that ensures each of the plurality of CPUs has enabled. Aspects include determining whether a second alias management group exists having a second set of control units that matches the set of paths of the first control unit and associating the first control unit with the second alias management group.

Managing and sharing alias devices across logical control units

Provided are a computer program product, system, and method for establishing copy pairs from primary volumes to secondary volumes in multiple secondary storage systems for a failover session. For each of the copy pairs, data is mirrored from the primary storage system to the associated secondary storage system in the copy pair. A failure is detected at the primary storage system. Selection is made of a selected secondary storage system of the secondary storage systems in response to detecting the failure, wherein a plurality of the secondary storage systems are available for selection. The selected secondary storage system is indicated as a new primary storage system to which host requests are directed.

Establishing copy pairs from primary volumes to secondary volumes in multiple secondary storage systems for a failover session

A method for improving system availability in data replication environments is disclosed herein. In one embodiment, such a method includes detecting a suspend trigger, where the suspend trigger indicates that data mirroring between a primary volume and a secondary volume has been suspended. The method further detects a swap trigger some time after detecting the suspend trigger. The swap trigger indicates that I/O directed to the primary volume has failed. In the event the swap trigger is detected within a specified amount of time after detecting the suspend trigger, the method redirects I/O from the primary volume to the secondary volume. A corresponding system and computer program product are also disclosed.

System availability in PPRC failover environments

A sectioned ordered queue in an information handling system comprises a plurality of queue sections arranged in order from a first queue section to a last queue section. Each queue section contains one or more queue entries that correspond to available ranges of real storage locations and are arranged in order from a first queue entry to a last queue entry. Each queue section and each queue entry in the queue sections having a weight factor defined for it. Each queue entry has an effective weight factor formed by combining the weight factor defined for the queue section with the weight factor defined for the queue entry. A new entry is added to the last queue section to indicate a newly available corresponding storage location, and one or more queue entries are deleted from the first section of the queue to indicate that the corresponding storage locations are no longer available. Various processes associated with a real storage manager are responsible for keeping the queue sections in balance, updating the queue sections, and removing entries from the queue to &ldquo;steal&rdquo; real storage frames.

Method and apparatus for maintaining order in a queue by combining entry weights and queue weights

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Poughkeepsie, NY, United States of America

Tri M Hoang