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CICS Transaction Server for z/OS
Version 4 Release 1
Recovery and Restart Guide
SC34-7012-01
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CICS Transaction Server for z/OS Version 4 Release 1 Recovery and Restart Guide SC34-7012-01
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Note Before using this information and the product it supports, read the information in “Notices” on page 243. This edition applies to Version 4 Release 1 of CICS Transaction Server for z/OS (product number 5655-S97) and to all subsequent releases and modifications until otherwise indicated in new editions. © Copyright IBM Corporation 1982, 2010. US Government Users Restricted Rights – Use, duplication or disclosure restricted by GSAADP Schedule Contract with IBM Corp.
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Contents Third quiesce stage...........26 Preface ..............vii Warm keypoints............27 What this book is about..........vii Shunted units of work at shutdown.....27 Who should read this book.........vii Flushing journal buffers.........28 What you need to know to understand this book vii Immediate shutdown processing (PERFORM How to use this book...........vii SHUTDOWN IMMEDIATE).........28 Shutdown requested by the operating system . . . 29 Changes in CICS Transaction Server for Uncon
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Journal names and journal models......58 Chapter 9. Communication error Terminal control resources ........58 processing.............97 Distributed transaction resources......59 Terminal error processing..........97 URIMAP definitions and virtual hosts ....59 Node error program (DFHZNEP)......97 Terminal error program (DFHTEP) .....97 Chapter 6. CICS emergency restart . . 61 Intersystem communication failures ......98 Recovering after a CICS failure........61 Recovering information from the syst
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Input extrapartition data sets.......134 Omitting the PEP............165 Output extrapartition data sets ......135 Using post-initialization (PLTPI) programs . . 135 Chapter 15. Resolving retained locks Recovery for temporary storage.......135 on recoverable resources......167 Backward recovery ..........135 Quiescing RLS data sets..........167 Forward recovery...........136 The RLS quiesce and unquiesce functions . . . 168 Recovery for Web services.........136 Switching from RLS to non-RLS acce
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Forward recovery logging........215 Disaster recovery facilities.........238 Forward recovery...........216 MVS system logger recovery support ....238 Recovering VSAM spheres with AIXs ....217 CICS VSAM Recovery QSAM copy.....239 An assembler program that calls DFSMS callable Remote Recovery Data Facility support....239 services ...............218 CICS VR shadowing..........239 CICS emergency restart considerations.....239 Indoubt and backout failure support ....239 Chapter 19. Disaster recovery
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Preface What this book is about ® This book contains guidance about determining your CICS recovery and restart needs, deciding which CICS facilities are most appropriate, and implementing your design in a CICS region. The information in this book is generally restricted to a single CICS region. For information about interconnected CICS regions, see the CICS Intercommunication Guide. This manual does not describe recovery and restart for the CICS front end programming interface. For information o
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viii CICS TS for z/OS 4.1: Recovery and Restart Guide
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Changes in CICS Transaction Server for z/OS, Version 4 Release 1 For information about changes that have been made in this release, please refer to What's New in the information center, or the following publications: v CICS Transaction Server for z/OS What's New v CICS Transaction Server for z/OS Upgrading from CICS TS Version 3.2 v CICS Transaction Server for z/OS Upgrading from CICS TS Version 3.1 v CICS Transaction Server for z/OS Upgrading from CICS TS Version 2.3 Any technical changes that
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x CICS TS for z/OS 4.1: Recovery and Restart Guide
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Part 1. CICS recovery and restart concepts It is very important that a transaction processing system such as CICS can restart and recover following a failure. This section describes some of the basic concepts of the recovery and restart facilities provided by CICS. © Copyright IBM Corp. 1982, 2010 1
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2 CICS TS for z/OS 4.1: Recovery and Restart Guide
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Chapter 1. Recovery and restart facilities Problems that occur in a data processing system could be failures with communication protocols, data sets, programs, or hardware. These problems are potentially more severe in online systems than in batch systems, because the data is processed in an unpredictable sequence from many different sources. Online applications therefore require a system with special mechanisms for recovery and restart that batch systems do not require. These mechanisms ensure
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In general, forward recovery is applicable to data set failures, or failures in similar data resources, which cause data to become unusable because it has been corrupted or because the physical storage medium has been damaged. Minimizing the effect of failures An online system should limit the effect of any failure. Where possible, a failure that affects only one user, one application, or one data set should not halt the entire system. Furthermore, if processing for one user is forced to stop pr
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Another way is to shut down CICS with an immediate shutdown and perform the forward recovery, after which a CICS emergency restart performs the backward recovery. Recoverable resources In CICS, a recoverable resource is any resource with recorded recovery information that can be recovered by backout. The following resources can be made recoverable: v CICS files that relate to: – VSAM data sets – BDAM data sets v Data tables (but user-maintained data tables are not recovered after a CICS failure,
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v In the event of an emergency restart, when CICS backs out all those transactions that were in-flight at the time of the CICS failure (emergency restart backout). Although these occur in different situations, CICS uses the same backout process in each case. CICS does not distinguish between dynamic backout and emergency restart backout. See Chapter6, “CICS emergency restart,” on page 61 for an explanation of how CICS reattaches failed in-flight units of work in order to perform transaction back
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The recovery manager also drives: v The backout processing for any units of work that were in a backout-failed state at the time of the CICS failure v The commit processing for any units of work that had not finished commit processing at the time of failure (for example, for resource definitions that were being installed when CICS failed) v The commit processing for any units of work that were in a commit-failed state at the time of the CICS failure See “Unit of work recovery” on page 73 for an
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Forward recovery journal names are of the form DFHJnn where nn is a number in the range 1–99 and is obtained from the forward recovery log id (FWDRECOVLOG) in the FILE resource definition. In this case, CICS creates a journal entry for the forward recovery log, which can be mapped by a JOURNALMODEL resource definition. Although this method enables user application programs to reference the log, and write user journal records to it, you are recommended not to do so. You should ensure that forward
