IBM SC34-7012-01 manual Contents

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, 2010 iii