Browse Prior Art Database

Minimise fuzzy backup costs by initial filtering of eligible messages

IP.com Disclosure Number: IPCOM000015474D
Original Publication Date: 2002-Jan-13
Included in the Prior Art Database: 2003-Jun-20
Document File: 2 page(s) / 30K

Publishing Venue

IBM

Abstract

Disclosed is a method for improving the performance of a backup process by quickly determining which messages are eligible for backup.

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Minimise fuzzy backup costs by initial filtering of eligible messages

Disclosed is a method for improving the performance of a backup
process by quickly determining which messages are eligible for
backup.

Background

     Queue managers such as IBM MQSeries* queue managers and
similar programs provide facilities for storing messages on
queues. For certain classes of message, queue managers provide
recovery facilities. These recovery facilities can re-create a
queue when the primary storage used to hold its messages fails
and then restore the messages so that the final state of the
queue is the same as at the time of the storage failure.

     Typically the recovery facility restores messages from a
back-up copy of the queue (possibly a "fuzzy" back-up) and then
replays the queue manager's log to reapply changes to the queue.

     Products such as MQSeries for OS/390* provide support for
shared queues. This new support uses coupling facility (CF) list
structures as the primary storage for shared queues. Messages on
shared queues are stored as list entries in CF list structures.
Applications running on multiple queue managers in the same queue
sharing group (QSG) anywhere in a parallel sysplex can then
access these shared queue messages.

Problem Description

     Only messages that have been marked as persistent (by the
creator of the message) need to be recorded on the queue
manager's log and included in back-up copies of the CF structures
since manufacturers of such products typically only guarantee to
be able to restore persistent messages followin...