SC34-7012-01
Recovery and Restart Guide
CICS Transaction Server for z/OS
Version 4 Release
Page
SC34-7012-01
Recovery and Restart Guide
CICS Transaction Server for z/OS
Version 4 Release
Copyright IBM Corporation 1982
Chapter 2. Resource recovery in CICS
Contents
Part 1. CICS recovery and restart concepts
Part 2. Recovery and restart processes
Chapter 8. Unit of work recovery and
Part 3. Implementing recovery and
Chapter 9. Communication error
recovery
Chapter 18. Backup-while-open BWO
Chapter 13. Programming for recovery
Chapter 16. Moving recoverable data
Chapter 17. Forward recovery
Notices
Chapter 19. Disaster recovery
Accessibility
Part 4. Appendixes
Who should read this book
How to use this book
Preface
What this book is about
viii CICS TS for z/OS 4.1 Recovery and Restart Guide
Changes in CICS Transaction Server for z/OS, Version 4 Release
x CICS TS for z/OS 4.1 Recovery and Restart Guide
Part 1. CICS recovery and restart concepts
2 CICS TS for z/OS 4.1 Recovery and Restart Guide
Chapter 1. Recovery and restart facilities
Maintaining the integrity of data
Logging changes
Minimizing the effect of failures
The role of CICS
4 CICS TS for z/OS 4.1 Recovery and Restart Guide
CICS backward recovery backout
Recoverable resources
Emergency restart backout
Dynamic transaction backout
Forward recovery of CICS data sets
CICS forward recovery
Failures that require CICS recovery processing
CICS recovery processing following a communication failure
Forward recovery for non-VSAM resources
XCF/MRO partner failures
CICS recovery processing following a transaction failure
CICS recovery processing following a system failure
10 CICS TS for z/OS 4.1 Recovery and Restart Guide
v Back out recoverable resources
12 CICS TS for z/OS 4.1 Recovery and Restart Guide
Chapter 2. Resource recovery in CICS
Units of work
Shunted units of work
Active and retained states for locks
Locks
EXEC CICS CREATE TERMINAL
Synchronization points
EXEC CICS CREATE TERMINAL EXEC CICS CREATE CONNECTION COMPLETE
EXEC CICS DISCARD CONNECTION EXEC CICS DISCARD TERMINAL
Examples of synchronization points
EXEC CICS CREATE CONNECTION COMPLETE EXEC CICS DISCARD CONNECTION
EXEC CICS DISCARD TERMINAL
CICS recovery manager
Figure 3. CICS recovery manager and resources it works with
FC/RLS
Recovery
v Coordinating recoverable conversations to remote nodes
Coordinating updates to local resources
Managing indoubt units of work
Coordinating updates in distributed units of work
Resynchronization after system or connection failure
CICS system log
Information recorded on the system log
Forward recovery logs
System activity keypoints
User journals and automatic journaling
Input or output messages from terminals accessed through VTAM
24 CICS TS for z/OS 4.1 Recovery and Restart Guide
Chapter 3. Shutdown and restart recovery
Normal shutdown processing
First quiesce stage
Third quiesce stage
Second quiesce stage
Shunted units of work at shutdown
Warm keypoints
Flushing journal buffers
Immediate shutdown processing PERFORM SHUTDOWN IMMEDIATE
PERFORM IMMEDIATE not recommended
Shutdown requested by the operating system
Uncontrolled termination
The shutdown assist transaction
30 CICS TS for z/OS 4.1 Recovery and Restart Guide
Global catalog
Cataloging CICS resources
Local catalog
Shutdown initiated by CICS log manager
Effect of problems with the system log
DFHRM0405
How the state of the CICS region is reconstructed
DFHRM0402
DFHRM0403 and DFHRM0404
About this task
Overriding the type of start indicator
Warm restart
Emergency restart
Recovery of data during an emergency restart
Cold start
An initial start of CICS
Dynamic RLS restart
MNPS, multinode persistent sessions
Recovery with VTAM persistent sessions
Running with persistent sessions support
SNPS, single-node persistent sessions
Situations in which sessions are not reestablished
Running without persistent sessions support
Situations in which VTAM does not retain sessions
SET VTAM FORCECLOSE SET VTAM IMMCLOSE SET VTAM CLOSED
regions that do have persistent sessions support
42 CICS TS for z/OS 4.1 Recovery and Restart Guide
Part 2. Recovery and restart processes
44 CICS TS for z/OS 4.1 Recovery and Restart Guide
Chapter 4. CICS cold start
Starting CICS with the START=COLD parameter
About this task
VSAM
Files
Data tables
Temporary storage
Transient data
Temporary storage data sharing server
LIBRARY resources
Resource definitions dynamically installed
Transactions
Journal names and journal models
Terminal control resources
Committing and cataloging resources installed from the CSD
Single resource install
Monitoring and statistics
Starting CICS with the START=INITIAL parameter
Installable set install
Distributed transaction resources
Dump table
information saved in the system log from a previous run. The primary and secondary system log streams are purged and CICS begins writing a new system log
52 CICS TS for z/OS 4.1 Recovery and Restart Guide
Rebuilding the CICS state after a normal shutdown
Chapter 5. CICS warm restart
Files
Reconnecting to SMSVSAM for RLS access
Data set name blocks
Recreating non-RLS retained locks
Temporary storage
TDINTRA=NOEMPTY the default
TDINTRA=EMPTY
Trigger levels for TERMINAL and SYSTEM only
Programs
No autoinstall for programs
Transactions
LIBRARY resources
Autoinstall for programs
Start requests
Monitoring and statistics
Terminal control resources
CSD-defined resource definitions
TCAM and sequential BSAM devices
Journal names and journal models
URIMAP definitions and virtual hosts
v Different TCT from last run. CICS installs the TCT only, and does not apply the warm keypoint information, effectively making this a cold start for these devices
Distributed transaction resources
60 CICS TS for z/OS 4.1 Recovery and Restart Guide
Driving backout processing for in-flight units of work
Recovering after a CICS failure
Recovering information from the system log
Chapter 6. CICS emergency restart
62 CICS TS for z/OS 4.1 Recovery and Restart Guide
Effect of delayed recovery on PLTPI processing
Other backout processing
Rebuilding the CICS state after an abnormal termination
Temporary storage
Reconnecting to SMSVSAM for RLS access
RLS restart processing and orphan locks
Recreating non-RLS retained locks
CSD-defined resource definitions
64 CICS TS for z/OS 4.1 Recovery and Restart Guide
Start requests
Terminal control resources
is successful, but CICS abnormally terminates before the catalog can be updated, CICS recovers the information from the forward recovery records on the system log
Distributed transaction resources
TCAM and sequential BSAM devices
66 CICS TS for z/OS 4.1 Recovery and Restart Guide
Chapter 7. Automatic restart management
CICS ARM processing
Restrictions
Before you begin
Registering with ARM
Waiting for predecessor subsystems
De-registering from ARM
Chapter 7. Automatic restart management
Failing to register
ARM couple data sets
CICS restart JCL and parameters
Connecting to VTAM
Workload policies
CICS START options
Server ARM processing
The COVR transaction
Messages associated with automatic restart
Automatic restart of CICS data-sharing servers
Server initialization parameters for ARM support
Server commands for ARM support
CANCEL RESTART=NOYES
Waiting on events during initialization
Commit-failed
Chapter 8. Unit of work recovery and abend processing
Unit of work recovery
In-flight-failed
Transaction backout
Backout-failed
Indoubt-failed
Files
BDAM files and VSAM ESDS files
CICS data tables
START requests
START with recoverable data no PROTECT
Intrapartition transient data
Auxiliary temporary storage
Restart of started transactions
START with recoverable data PROTECT
START with nonrecoverable data no PROTECT
START with nonrecoverable data PROTECT
EXEC CICS CANCEL requests
Basic mapping support BMS messages
Auxiliary temporary storage
Backout-failed recovery
Disposition of data sets after backout failures
I/O error
Transient data
Retrying backout-failed units of work
Open error
Logical delete not performed
SMSVSAM server failure
Coupling facility cache structure failure
DFSMSdss non-BWO backup in progress
Duplicate key error
SMSVSAM server recycle during backout
Commit-failed recovery
Lock structure full error
None of the above
Files
Indoubt failure recovery
Investigating an indoubt failure
Intrapartition transient data
Auxiliary temporary storage
The WAITSTATE of Shunted shows that this UOW has been suspended
We can now see that
Cache failure support
Recovery from failures associated with the coupling facility
About this task
Lost locks recovery
Rebuilding the lock structure
Notifying CICS of SMSVSAM restart
90 CICS TS for z/OS 4.1 Recovery and Restart Guide
Performing lost locks recovery for failed units of work
MVS system recovery and sysplex recovery
Connection failure to a coupling facility cache structure
Connection failure to a coupling facility lock structure
Exit code
Transaction abend processing
Transaction restart
Abnormal termination of a task
Processing operating system abends and program checks
Actions taken at transaction failure
v If a match is not found, CICS is terminated
96 CICS TS for z/OS 4.1 Recovery and Restart Guide
Terminal error program DFHTEP
Chapter 9. Communication error processing
Terminal error processing
Node error program DFHZNEP
Intersystem communication failures
Part 3. Implementing recovery and restart
100 CICS TS for z/OS 4.1 Recovery and Restart Guide
Chapter 10. Planning aspects of recovery
Questions relating to recovery requirements
Application design considerations
Validate the recovery requirements statement
About this task
Designing the end user’s restart procedure
End user’s standby procedures
Communications between application and user
Security
System definitions for recovery-related functions
System recovery table SRT
Resource definitions for recovery
Program list table PLT
Documentation and test plans
Transient data queues
Temporary storage table
v Forecast the exceptional conditions that can be expected
System logging
recovery purposes only
Forward recovery logging
Chapter 11. Defining system and general log streams
General log streams
Defining log streams to MVS
Defining system log streams
System log streams
Specifying a JOURNALMODEL resource definition
Without a JOURNALMODEL definition
With a JOURNALMODEL definition
Model log streams for CICS system logs
Recovery considerations
2-Way Sysplex
Activity keypointing
Varying the model log stream name
About this task
About this task
Keeping system log data to a minimum
Log-tail deletion
Moving units of work to the secondary log
About this task
About this task
Writing user-recovery data
Avoiding retention periods on the system log
Retrieving user records from the system log
About this task
Defining forward recovery log streams
About this task Procedure
Long-running transactions
What to do next
Model log streams for CICS general logs
Merging data on shared general log streams
Defining the log of logs
About this task
About this task
Log of logs failure
Reading log streams offline
About this task
About this task
Adjusting local time
Effect of daylight saving time changes
Time stamping log and journal records
Offline utility program, DFHJUP
122 CICS TS for z/OS 4.1 Recovery and Restart Guide
RESTARTNOYES
Chapter 12. Defining recoverability for CICS-managed resources
Recovery for transactions
Defining transaction recovery attributes
ACTIONBACKOUTCOMMIT
Indoubt options for distributed transactions
SPURGENOYES
TPURGENOYES
Sharing data sets with batch jobs
Recovery for files
File-owning regions and RLS access
VSAM files
Backward recovery
Basic direct access method BDAM
Defining files as recoverable resources
Forward recovery
BACKUPTYPEDYNAMIC
VSAM files accessed in non-RLS mode
RECOVERYALL
RECOVERYBACKOUTONLY
NONE
VSAM files accessed in RLS mode
Inquiring on recovery attributes
LOGNONEUNDOALL
Overriding open failures at the XFCNREC global user exit
File recovery attribute consistency checking non-RLS
BDAM files
The CSD data set
About this task
CICS responses to file open requests
Backward recovery
Implementing forward recovery with user-written utilities
Implementing forward recovery with CICS VSAM Recovery MVS/ESA
Recovery for intrapartition transient data
Physical recovery
Logical recovery
No recovery
Forward recovery
Input extrapartition data sets
Recovery for extrapartition transient data
Backward recovery
Using post-initialization PLTPI programs
Recovery for temporary storage
Output extrapartition data sets
GROUPTSRECOV PREFIXDF LOCATIONAUXILIARY RECOVERYYES
Recovery for Web services
Configuring CICS to support persistent messages
Forward recovery
Procedure
Defining local queues in a service provider
Procedure
Results What to do next
Persistent message processing
Error processing
For example, your recovery transaction could
140 CICS TS for z/OS 4.1 Recovery and Restart Guide
About this task Procedure
Chapter 13. Programming for recovery
Designing applications for recovery
Splitting the application into transactions
142 CICS TS for z/OS 4.1 Recovery and Restart Guide
Example What to do next Relationships between processing units
Procedure
SAA-compatible applications
Program design
Dividing transactions into units of work
Processing dialogs with users
Conversational processing
Pseudoconversational processing
CICS recoverable resources
Mechanisms for passing data between transactions
Main storage areas
User files and DL/I and DB2 databases
Designing to avoid transaction deadlocks
Temporary storage auxiliary
Transient data queues
Procedure
Implications of interval control START requests
Terminal paging through BMS
Using transient data queues
Implications of automatic task initiation TD trigger level
Implications of presenting large amounts of data to the user
About this task
Managing transaction and system failures
Transaction failures
About this task
HANDLE ABEND commands
EXEC CICS SYNCPOINT ROLLBACK command
Dynamic transaction backout
Transaction restart after DTB
Use of the program error program DFHPEP
System failures
Handling abends and program level abend exits
Processing the IOERR condition
Command
Information provided
START TRANSID commands
PL/I programs and error handling
Locking enqueuing on resources in application programs
Nonrecoverable files
Implicit locking for files
About this task
Recoverable files
v READ for UPDATE v WRITE v DELETE
Implicit enqueuing on logically recoverable TD destinations
Implicit enqueuing on recoverable temporary storage queues
v WRITEQ TD v READQ TD v DELETEQ TD
Sequential methods HSAM, HISAM, SHISAM
Implicit enqueuing on DL/I databases with DBCTL
Explicit enqueuing by the application programmer
Direct methods HDAM, HIDAM
deadlock
Possibility of transaction deadlock
Where you can add your own code
User exits for transaction backout
About this task
Procedure
XRCINIT exit
XRCINPT exit
XFCBFAIL global user exit
Coding transaction backout exits
XFCLDEL global user exit
XFCBOVER global user exit
XFCBOUT global user exit
About this task
Chapter 14. Using a program error program PEP
The CICS-supplied PEP
Procedure
Your own PEP
Omitting the PEP
Chapter 14. Using a program error program PEP
About this task
166 CICS TS for z/OS 4.1 Recovery and Restart Guide
About this task
Chapter 15. Resolving retained locks on recoverable resources
Quiescing RLS data sets
About this task
Illustration of the quiesce flow across two CICS regions
The RLS quiesce and unquiesce functions
Chapter 15. Resolving retained locks on recoverable resources
Other quiesce interface functions
Non-BWO data set backup start
Forward recovery complete
Non-BWO data set backup end
BWO backup start
BWO backup end
Quiesce coupling facility cache available
Switching from RLS to non-RLS access mode
Lost locks recovery complete
Exception for read-only operations
What can prevent a switch to non-RLS access mode?
About this task
Resolving retained locks before opening data sets in non-RLS mode
Investigating which retained locks are held and why
Procedure
INQUIRE DSNAME
INQUIRE UOWDSNFAIL
About this task
176 CICS TS for z/OS 4.1 Recovery and Restart Guide
SHCDS LIST subcommands
Resolving retained locks and preserving data integrity
About this task Procedure
About this task
Choosing data availability over data integrity
DFH0BAT2
CEMT command examples
The batch-enabling sample programs
DFH0BAT1
NORMAL
SET DSNAME’RLS.ACCOUNTS.ESDS.DBASE1’ RETRY
STATUS RESULTS - OVERTYPE TO MODIFY
DsnRLS.ACCOUNTS.ESDS.DBASE1
Overriding retained locks
The PERMITNONRLSUPDATE subcommand
The DENYNONRLSUPDATE subcommand
A special case lost locks
Post-batch processing
Coupling facility data table retained locks
About this task
Chapter 16. Moving recoverable data sets that have retained locks
Procedure for moving a data set with retained locks
Using the REPRO method
SHCDS FRBIND
SHCDS FRRESETRR
SHCDS FRSETRR
SHCDS FRUNBIND
Using the EXPORT and IMPORT functions
Chapter 16. Moving recoverable data sets that have retained locks
About this task
About this task
Rebuilding alternate indexes
Chapter 17. Forward recovery procedures
Forward recovery of data sets accessed in RLS mode
About this task
5. Restore the backup
Recovery of data set with volume still available
3. Issue FRSETRR
4. Issue FRUNBIND
9. Alter the new data set name
Recovery of data set with loss of volume
10. Issue the FRBIND subcommand
11. Issue the FRRESETRR subcommand
Volume recovery procedure using CFVOL QUIESCE
1. VARY SMS,CFVOLvolser,QUIESCE
Example of recovery using data set backup
5. We terminated the SMSVSAM servers using the MVS command
INQUIRE UOWDSNFAIL DSNRLSADSW.VF01D.BANKACCT
194 CICS TS for z/OS 4.1 Recovery and Restart Guide
These commands are issued to each CICS AOR that requires access
196 CICS TS for z/OS 4.1 Recovery and Restart Guide
Example of recovery using volume backup
Catalog recovery
4. Run the forward recovery utility
Forward recovery of data sets accessed in non-RLS mode
Procedure for failed RLS mode forward recovery operation
3. Restore the backup
1. Tidy up any outstanding CICS recovery work, as follows
1 Force shunted indoubt units of work using SET DSNAME
Procedure for failed non-RLS mode forward recovery operation
202 CICS TS for z/OS 4.1 Recovery and Restart Guide
Chapter 18. Backup-while-open BWO
BWO and backups
BWO and concurrent copy
Previous product
BWO requirements
Component name
Full DFSMS/MVS name
Hardware requirements
Which data sets are eligible for BWO
VSAM control interval or control area split
TYPECICS
Specifying BWO using access method services
How you request BWO
Results
About this task
Specifying BWO on CICS file resource definitions
Procedure
Systems administration
Removing BWO attributes
Batch jobs
BWO processing
First file opened in non-RLS mode against a cluster
File opening
Back-level data sets
Subsequent files opened when use count is zero
Subsequent files opened when use count is not zero
Restriction for VSAM upgrade set
File closing non-RLS mode
Immediate or uncontrolled shutdown
Data set backup and restore
Shutdown and restart
Controlled shutdown
Invalid state changes for BWO attributes
VSAM access method services
Non-SMS managed storage
Forward recovery logging
Data set restore
Data sets
Forward recovery
Recovery point non-RLS mode
About this task
Recovering VSAM spheres with AIXs
An assembler program that calls DFSMS callable services
DATEPACK
DATETIME
DTTENTHS
RECOVPTP
LOAD
220 CICS TS for z/OS 4.1 Recovery and Restart Guide
PRGCONT
BWOFLAGS12,ZEROES
END PROG
222 CICS TS for z/OS 4.1 Recovery and Restart Guide
Why have a disaster recovery plan?
Chapter 19. Disaster recovery
Disaster recovery testing
Six tiers of solutions for off-site recovery
Tier 0 no off-site data
Tier 1 - physical removal
The drawbacks are
Tier 2 - physical removal with hot site
Tier 3 - electronic vaulting
Tier
Tier 0-3 solutions
Tier 0
Tier 4 - active secondary site
230 CICS TS for z/OS 4.1 Recovery and Restart Guide
Figure 22. Disaster recovery tier 4 active secondary site
Tier 6 - minimal to zero data loss
Tier 5 - two-site, two-phase commit
Figure 24 summarizes the tier 6 solution
Tier 4
Tier 4-6 solutions
Peer-to-peer remote copy PPRC and extended remote copy XRC
Disaster recovery and high availability
Use XRC for high volume transactions
PPRC or XRC?
Use PPRC for high value transactions
236 CICS TS for z/OS 4.1 Recovery and Restart Guide
Remote Recovery Data Facility
Other benefits of PPRC and XRC
Forward recovery
RRDF
Choosing between RRDF and 3990-6 solutions
Disaster recovery personnel considerations
About this task
238 CICS TS for z/OS 4.1 Recovery and Restart Guide
Disaster recovery facilities
MVS system logger recovery support
Returning to your primary site
CICS VR shadowing
CICS VSAM Recovery QSAM copy
Remote Recovery Data Facility support
Remote site recovery for RLS-mode data sets
Final summary
Copyright IBM Corp. 1982
Part 4. Appendixes
242 CICS TS for z/OS 4.1 Recovery and Restart Guide
Notices
244 CICS TS for z/OS 4.1 Recovery and Restart Guide
Trademarks
CICS books for CICS Transaction Server for z/OS
Access to CICS
Administration
Bibliography
General
Administration and Management
CICSPlex SM books for CICS Transaction Server for z/OS
Other CICS publications
Accessibility
248 CICS TS for z/OS 4.1 Recovery and Restart Guide
Index A
files continued
DL/I continued
locking continued
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