IBM SC34-7012-01 - Manual (Page 5)

Contents
Preface . . . . . . . . . . . . . . vii
What this book is about . . . . . . . . . . vii
Who should read this book . . . . . . . . . vii
What you need to know to understand this book vii
How to use this book . . . . . . . . . . . vii
Changes in CICS Transaction Server for
z/OS, Version 4 Release 1 . . . . . . . ix
Part 1. CICS recovery and restart
concepts . . . . . . . . . . . . . . 1
Chapter 1. Recovery and restart facilities 3
Maintaining the integrity of data . . . . . . . 3
Minimizing the effect of failures . . . . . . . . 4
The role of CICS . . . . . . . . . . . . . 4
Recoverable resources . . . . . . . . . . . 5
CICS backward recovery (backout) . . . . . . . 5
Dynamic transaction backout . . . . . . . . 6
Emergency restart backout. . . . . . . . . 6
CICS forward recovery . . . . . . . . . . . 7
Forward recovery of CICS data sets. . . . . . 7
Failures that require CICS recovery processing . . . 8
CICS recovery processing following a
communication failure .
. . . . . . . . . 8
CICS recovery processing following a transaction
failure .
. . . . . . . . . . . . . . 10
CICS recovery processing following a system
failure .
. . . . . . . . . . . . . . 10
Chapter 2. Resource recovery in CICS 13
Units of work . . . . . . . . . . . . . 13
Shunted units of work . . . . . . . . . . 13
Locks . . . . . . . . . . . . . . . 14
Synchronization points . . . . . . . . . 15
CICS recovery manager . . . . . . . . . . 17
Managing the state of each unit of work. . . . 18
Coordinating updates to local resources . . . . 19
Coordinating updates in distributed units of
work
. . . . . . . . . . . . . . . 20
Resynchronization after system or connection
failure .
. . . . . . . . . . . . . . 21
CICS system log . . . . . . . . . . . . . 21
Information recorded on the system log . . . . 21
System activity keypoints. . . . . . . . . 22
Forward recovery logs . . . . . . . . . . . 22
User journals and automatic journaling . . . . . 22
Chapter 3. Shutdown and restart
recovery . . . . . . . . . . . . . . 25
Normal shutdown processing . . . . . . . . 25
First quiesce stage . . . . . . . . . . . 25
Second quiesce stage . . . . . . . . . . 26
Third quiesce stage . . . . . . . . . . . 26
Warm keypoints . . . . . . . . . . . . 27
Shunted units of work at shutdown . . . . . 27
Flushing journal buffers . . . . . . . . . 28
Immediate shutdown processing (PERFORM
SHUTDOWN IMMEDIATE) .
. . . . . . . . 28
Shutdown requested by the operating system . . . 29
Uncontrolled termination . . . . . . . . . . 30
The shutdown assist transaction . . . . . . . 30
Cataloging CICS resources . . . . . . . . . 31
Global catalog . . . . . . . . . . . . 31
Local catalog . . . . . . . . . . . . . 32
Shutdown initiated by CICS log manager . . . . 33
Effect of problems with the system log . . . . 33
How the state of the CICS region is reconstructed 34
Overriding the type of start indicator . . . . . 35
Warm restart . . . . . . . . . . . . . 35
Emergency restart . . . . . . . . . . . 35
Cold start . . . . . . . . . . . . . . 36
Dynamic RLS restart . . . . . . . . . . 37
Recovery with VTAM persistent sessions . . . . 38
Running with persistent sessions support . . . 38
Running without persistent sessions support . . 40
Part 2. Recovery and restart
processes . . . . . . . . . . . . . 43
Chapter 4. CICS cold start . . . . . . 45
Starting CICS with the START=COLD parameter . . 45
Files . . . . . . . . . . . . . . . . 46
Temporary storage . . . . . . . . . . . 47
Transient data . . . . . . . . . . . . 47
Transactions . . . . . . . . . . . . . 48
Journal names and journal models. . . . . . 48
LIBRARY resources . . . . . . . . . . . 48
Programs . . . . . . . . . . . . . . 48
Start requests (with and without a terminal) . . 48
Resource definitions dynamically installed . . . 48
Monitoring and statistics . . . . . . . . . 49
Terminal control resources . . . . . . . . 49
Distributed transaction resources . . . . . . 50
Dump table . . . . . . . . . . . . . 50
Starting CICS with the START=INITIAL parameter 50
Chapter 5. CICS warm restart . . . . . 53
Rebuilding the CICS state after a normal shutdown 53
Files . . . . . . . . . . . . . . . . 54
Temporary storage . . . . . . . . . . . 55
Transient data . . . . . . . . . . . . 55
Transactions . . . . . . . . . . . . . 56
LIBRARY resources . . . . . . . . . . . 56
Programs . . . . . . . . . . . . . . 56
Start requests . . . . . . . . . . . . . 57
Monitoring and statistics . . . . . . . . . 57
© Copyright IBM Corp. 1982, 2012 iii
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