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IBM SC34-7012-01 manual viii CICS TS for z/OS 4.1 Recovery and Restart Guide

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viiiCICS TS for z/OS 4.1: Recovery and Restart Guide

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IBM SC34-7012-01 manual viii CICS TS for z/OS 4.1 Recovery and Restart Guide

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Version 4 Release Recovery and Restart GuideCICS Transaction Server for z/OS SC34-7012-01Page Version 4 Release Recovery and Restart GuideCICS Transaction Server for z/OS SC34-7012-01Copyright IBM Corporation 1982 Part 2. Recovery and restart processes ContentsPart 1. CICS recovery and restart concepts Chapter 2. Resource recovery in CICSrecovery Part 3. Implementing recovery andChapter 9. Communication error Chapter 8. Unit of work recovery andChapter 17. Forward recovery Chapter 13. Programming for recoveryChapter 16. Moving recoverable data Chapter 18. Backup-while-open BWOPart 4. Appendixes Chapter 19. Disaster recoveryAccessibility NoticesWhat this book is about How to use this bookPreface Who should read this bookviii 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 Maintaining the integrity of data Chapter 1. Recovery and restart facilitiesLogging changes The role of CICS Minimizing the effect of failures4 CICS TS for z/OS 4.1 Recovery and Restart Guide Recoverable resources CICS backward recovery backoutDynamic transaction backout Emergency restart backoutCICS forward recovery Forward recovery of CICS data setsCICS recovery processing following a communication failure Failures that require CICS recovery processingForward recovery for non-VSAM resources XCF/MRO partner failures CICS recovery processing following a system failure CICS recovery processing following a transaction failure10 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 Units of work Chapter 2. Resource recovery in CICSShunted units of work Locks Active and retained states for locksEXEC CICS DISCARD CONNECTION EXEC CICS DISCARD TERMINAL Synchronization pointsEXEC CICS CREATE TERMINAL EXEC CICS CREATE CONNECTION COMPLETE EXEC CICS CREATE TERMINALEXEC CICS CREATE CONNECTION COMPLETE EXEC CICS DISCARD CONNECTION Examples of synchronization pointsEXEC CICS DISCARD TERMINAL CICS recovery manager v Coordinating recoverable conversations to remote nodes FC/RLSRecovery Figure 3. CICS recovery manager and resources it works withCoordinating updates to local resources Coordinating updates in distributed units of work Managing indoubt units of workCICS system log Resynchronization after system or connection failureInformation recorded on the system log System activity keypoints Forward recovery logsUser 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 Normal shutdown processing Chapter 3. Shutdown and restart recoveryFirst quiesce stage Second quiesce stage Third quiesce stageWarm keypoints Shunted units of work at shutdownImmediate shutdown processing PERFORM SHUTDOWN IMMEDIATE Flushing journal buffersPERFORM IMMEDIATE not recommended Shutdown requested by the operating system The shutdown assist transaction Uncontrolled termination30 CICS TS for z/OS 4.1 Recovery and Restart Guide Cataloging CICS resources Global catalogLocal catalog Effect of problems with the system log Shutdown initiated by CICS log managerDFHRM0403 and DFHRM0404 How the state of the CICS region is reconstructedDFHRM0402 DFHRM0405Emergency restart Overriding the type of start indicatorWarm restart About this taskCold start Recovery of data during an emergency restartAn initial start of CICS Dynamic RLS restart SNPS, single-node persistent sessions Recovery with VTAM persistent sessionsRunning with persistent sessions support MNPS, multinode persistent sessionsSituations in which sessions are not reestablished Situations in which VTAM does not retain sessions Running without persistent sessions supportSET 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 Starting CICS with the START=COLD parameter Chapter 4. CICS cold startAbout this task Files VSAMTemporary storage data sharing server Temporary storageTransient data Data tablesJournal names and journal models Resource definitions dynamically installedTransactions LIBRARY resourcesMonitoring and statistics Committing and cataloging resources installed from the CSDSingle resource install Terminal control resourcesDump table Installable set installDistributed transaction resources Starting CICS with the START=INITIAL parameterinformation 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 Chapter 5. CICS warm restart Rebuilding the CICS state after a normal shutdownRecreating non-RLS retained locks Reconnecting to SMSVSAM for RLS accessData set name blocks FilesTrigger levels for TERMINAL and SYSTEM only TDINTRA=NOEMPTY the defaultTDINTRA=EMPTY Temporary storageLIBRARY resources No autoinstall for programsTransactions ProgramsStart requests Autoinstall for programsMonitoring and statistics Journal names and journal models CSD-defined resource definitionsTCAM and sequential BSAM devices Terminal control resourcesv 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 URIMAP definitions and virtual hostsDistributed transaction resources 60 CICS TS for z/OS 4.1 Recovery and Restart Guide Chapter 6. CICS emergency restart Recovering after a CICS failureRecovering information from the system log Driving backout processing for in-flight units of workRebuilding the CICS state after an abnormal termination Effect of delayed recovery on PLTPI processingOther backout processing 62 CICS TS for z/OS 4.1 Recovery and Restart GuideRecreating non-RLS retained locks Reconnecting to SMSVSAM for RLS accessRLS restart processing and orphan locks Temporary storageTerminal control resources 64 CICS TS for z/OS 4.1 Recovery and Restart GuideStart requests CSD-defined resource definitionsDistributed transaction 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 logTCAM and sequential BSAM devices 66 CICS TS for z/OS 4.1 Recovery and Restart Guide CICS ARM processing Chapter 7. Automatic restart managementRestrictions De-registering from ARM Registering with ARMWaiting for predecessor subsystems Before you beginCICS restart JCL and parameters Failing to registerARM couple data sets Chapter 7. Automatic restart managementWorkload policies Connecting to VTAMCICS START options Automatic restart of CICS data-sharing servers The COVR transactionMessages associated with automatic restart Server ARM processingWaiting on events during initialization Server commands for ARM supportCANCEL RESTART=NOYES Server initialization parameters for ARM supportIn-flight-failed Chapter 8. Unit of work recovery and abend processingUnit of work recovery Commit-failedBackout-failed Transaction backoutIndoubt-failed BDAM files and VSAM ESDS files FilesCICS data tables Auxiliary temporary storage START with recoverable data no PROTECTIntrapartition transient data START requestsSTART with nonrecoverable data PROTECT START with recoverable data PROTECTSTART with nonrecoverable data no PROTECT Restart of started transactionsBasic mapping support BMS messages EXEC CICS CANCEL requestsBackout-failed recovery Auxiliary temporary storageRetrying backout-failed units of work I/O errorTransient data Disposition of data sets after backout failuresLogical delete not performed Open errorSMSVSAM server failure SMSVSAM server recycle during backout DFSMSdss non-BWO backup in progressDuplicate key error Coupling facility cache structure failureLock structure full error Commit-failed recoveryNone of the above Indoubt failure recovery FilesIntrapartition transient data Investigating an indoubt failureAuxiliary temporary storage The WAITSTATE of Shunted shows that this UOW has been suspended We can now see that Recovery from failures associated with the coupling facility Cache failure supportNotifying CICS of SMSVSAM restart Lost locks recoveryRebuilding the lock structure About this taskPerforming lost locks recovery for failed units of work 90 CICS TS for z/OS 4.1 Recovery and Restart GuideConnection failure to a coupling facility cache structure MVS system recovery and sysplex recoveryConnection failure to a coupling facility lock structure Transaction abend processing Exit codeAbnormal termination of a task Transaction restartActions taken at transaction failure Processing operating system abends and program checksv If a match is not found, CICS is terminated 96 CICS TS for z/OS 4.1 Recovery and Restart Guide Node error program DFHZNEP Chapter 9. Communication error processingTerminal error processing Terminal error program DFHTEPIntersystem communication failures Part 3. Implementing recovery and restart 100 CICS TS for z/OS 4.1 Recovery and Restart Guide Questions relating to recovery requirements Chapter 10. Planning aspects of recoveryApplication design considerations Validate the recovery requirements statement Communications between application and user Designing the end user’s restart procedureEnd user’s standby procedures About this taskResource definitions for recovery System definitions for recovery-related functionsSystem recovery table SRT SecurityTemporary storage table Documentation and test plansTransient data queues Program list table PLTv Forecast the exceptional conditions that can be expected Chapter 11. Defining system and general log streams recovery purposes onlyForward recovery logging System loggingSystem log streams Defining log streams to MVSDefining system log streams General log streamsWithout a JOURNALMODEL definition Specifying a JOURNALMODEL resource definitionWith a JOURNALMODEL definition Recovery considerations Model log streams for CICS system logs2-Way Sysplex Varying the model log stream name Activity keypointingAbout this task Keeping system log data to a minimum About this taskMoving units of work to the secondary log Log-tail deletionAbout this task Retrieving user records from the system log Writing user-recovery dataAvoiding retention periods on the system log About this taskLong-running transactions Defining forward recovery log streamsAbout this task Procedure About this taskModel log streams for CICS general logs What to do nextDefining the log of logs Merging data on shared general log streamsAbout this task About this task Log of logs failureReading log streams offline About this taskTime stamping log and journal records Adjusting local timeEffect of daylight saving time changes About this taskOffline utility program, DFHJUP 122 CICS TS for z/OS 4.1 Recovery and Restart Guide Defining transaction recovery attributes Chapter 12. Defining recoverability for CICS-managed resourcesRecovery for transactions RESTARTNOYESTPURGENOYES Indoubt options for distributed transactionsSPURGENOYES ACTIONBACKOUTCOMMITVSAM files Recovery for filesFile-owning regions and RLS access Sharing data sets with batch jobsForward recovery Basic direct access method BDAMDefining files as recoverable resources Backward recoveryRECOVERYBACKOUTONLY VSAM files accessed in non-RLS modeRECOVERYALL BACKUPTYPEDYNAMICLOGNONEUNDOALL VSAM files accessed in RLS modeInquiring on recovery attributes NONEThe CSD data set File recovery attribute consistency checking non-RLSBDAM files Overriding open failures at the XFCNREC global user exitCICS responses to file open requests About this taskRecovery for intrapartition transient data Implementing forward recovery with user-written utilitiesImplementing forward recovery with CICS VSAM Recovery MVS/ESA Backward recoveryLogical recovery Physical recoveryForward recovery No recoveryRecovery for extrapartition transient data Input extrapartition data setsOutput extrapartition data sets Using post-initialization PLTPI programsRecovery for temporary storage Backward recoveryForward recovery Recovery for Web servicesConfiguring CICS to support persistent messages GROUPTSRECOV PREFIXDF LOCATIONAUXILIARY RECOVERYYESResults What to do next Defining local queues in a service providerProcedure ProcedureError processing Persistent message processingFor example, your recovery transaction could 140 CICS TS for z/OS 4.1 Recovery and Restart Guide Splitting the application into transactions Chapter 13. Programming for recoveryDesigning applications for recovery About this task ProcedureExample What to do next Relationships between processing units 142 CICS TS for z/OS 4.1 Recovery and Restart GuideDividing transactions into units of work SAA-compatible applicationsProgram design ProcedureConversational processing Processing dialogs with usersPseudoconversational processing Mechanisms for passing data between transactions CICS recoverable resourcesMain storage areas Transient data queues Designing to avoid transaction deadlocksTemporary storage auxiliary User files and DL/I and DB2 databasesImplications of interval control START requests ProcedureImplications of presenting large amounts of data to the user Using transient data queuesImplications of automatic task initiation TD trigger level Terminal paging through BMSAbout this task Managing transaction and system failuresTransaction failures About this taskEXEC CICS SYNCPOINT ROLLBACK command HANDLE ABEND commandsDynamic transaction backout Handling abends and program level abend exits Use of the program error program DFHPEPSystem failures Transaction restart after DTBCommand Processing the IOERR conditionInformation provided PL/I programs and error handling START TRANSID commandsLocking enqueuing on resources in application programs Implicit locking for files Nonrecoverable filesAbout this task Recoverable files v READ for UPDATE v WRITE v DELETE Implicit enqueuing on recoverable temporary storage queues Implicit enqueuing on logically recoverable TD destinationsv WRITEQ TD v READQ TD v DELETEQ TD Direct methods HDAM, HIDAM Implicit enqueuing on DL/I databases with DBCTLExplicit enqueuing by the application programmer Sequential methods HSAM, HISAM, SHISAMPossibility of transaction deadlock deadlockUser exits for transaction backout Where you can add your own codeAbout this task XFCBFAIL global user exit XRCINIT exitXRCINPT exit ProcedureXFCBOUT global user exit XFCLDEL global user exitXFCBOVER global user exit Coding transaction backout exitsProcedure Chapter 14. Using a program error program PEPThe CICS-supplied PEP About this taskYour own PEP Chapter 14. Using a program error program PEP Omitting the PEPAbout this task 166 CICS TS for z/OS 4.1 Recovery and Restart Guide About this task Chapter 15. Resolving retained locks on recoverable resourcesQuiescing RLS data sets About this taskThe RLS quiesce and unquiesce functions Illustration of the quiesce flow across two CICS regionsChapter 15. Resolving retained locks on recoverable resources Non-BWO data set backup start Other quiesce interface functionsBWO backup end Non-BWO data set backup endBWO backup start Forward recovery completeException for read-only operations Switching from RLS to non-RLS access modeLost locks recovery complete Quiesce coupling facility cache availableWhat can prevent a switch to non-RLS access mode? Procedure Resolving retained locks before opening data sets in non-RLS modeInvestigating which retained locks are held and why About this taskINQUIRE UOWDSNFAIL INQUIRE DSNAMEAbout this task About this task Procedure SHCDS LIST subcommandsResolving retained locks and preserving data integrity 176 CICS TS for z/OS 4.1 Recovery and Restart GuideChoosing data availability over data integrity About this taskDFH0BAT1 CEMT command examplesThe batch-enabling sample programs DFH0BAT2DsnRLS.ACCOUNTS.ESDS.DBASE1 SET DSNAME’RLS.ACCOUNTS.ESDS.DBASE1’ RETRYSTATUS RESULTS - OVERTYPE TO MODIFY NORMALA special case lost locks The PERMITNONRLSUPDATE subcommandThe DENYNONRLSUPDATE subcommand Overriding retained locksPost-batch processing Coupling facility data table retained locks Using the REPRO method Chapter 16. Moving recoverable data sets that have retained locksProcedure for moving a data set with retained locks About this taskSHCDS FRUNBIND SHCDS FRRESETRRSHCDS FRSETRR SHCDS FRBINDChapter 16. Moving recoverable data sets that have retained locks Using the EXPORT and IMPORT functionsAbout this task Rebuilding alternate indexes About this taskForward recovery of data sets accessed in RLS mode Chapter 17. Forward recovery proceduresAbout this task 4. Issue FRUNBIND Recovery of data set with volume still available3. Issue FRSETRR 5. Restore the backup11. Issue the FRRESETRR subcommand Recovery of data set with loss of volume10. Issue the FRBIND subcommand 9. Alter the new data set nameVolume 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 194 CICS TS for z/OS 4.1 Recovery and Restart Guide INQUIRE UOWDSNFAIL DSNRLSADSW.VF01D.BANKACCTThese commands are issued to each CICS AOR that requires access Example of recovery using volume backup 196 CICS TS for z/OS 4.1 Recovery and Restart GuideCatalog recovery 3. Restore the backup Forward recovery of data sets accessed in non-RLS modeProcedure for failed RLS mode forward recovery operation 4. Run the forward recovery utility1. 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 BWO and backups Chapter 18. Backup-while-open BWOBWO and concurrent copy Full DFSMS/MVS name BWO requirementsComponent name Previous productWhich data sets are eligible for BWO Hardware requirementsVSAM control interval or control area split Results Specifying BWO using access method servicesHow you request BWO TYPECICSSpecifying BWO on CICS file resource definitions About this taskBatch jobs Systems administrationRemoving BWO attributes ProcedureBWO processing File opening First file opened in non-RLS mode against a clusterBack-level data sets Subsequent files opened when use count is not zero Subsequent files opened when use count is zeroFile closing non-RLS mode Restriction for VSAM upgrade setControlled shutdown Data set backup and restoreShutdown and restart Immediate or uncontrolled shutdownVSAM access method services Invalid state changes for BWO attributesData sets Forward recovery loggingData set restore Non-SMS managed storageRecovery point non-RLS mode Forward recoveryRecovering VSAM spheres with AIXs About this taskAn assembler program that calls DFSMS callable services RECOVPTP DATETIMEDTTENTHS DATEPACKBWOFLAGS12,ZEROES 220 CICS TS for z/OS 4.1 Recovery and Restart GuidePRGCONT LOADEND PROG 222 CICS TS for z/OS 4.1 Recovery and Restart Guide Chapter 19. Disaster recovery Why have a disaster recovery plan?Disaster recovery testing Tier 0 no off-site data Six tiers of solutions for off-site recoveryTier 1 - physical removal The drawbacks are Tier 3 - electronic vaulting Tier 2 - physical removal with hot siteTier Tier 0-3 solutions Tier 4 - active secondary site Tier 0Figure 22. Disaster recovery tier 4 active secondary site 230 CICS TS for z/OS 4.1 Recovery and Restart GuideTier 5 - two-site, two-phase commit Tier 6 - minimal to zero data lossFigure 24 summarizes the tier 6 solution Tier 4-6 solutions Tier 4Disaster recovery and high availability Peer-to-peer remote copy PPRC and extended remote copy XRCPPRC or XRC? Use XRC for high volume transactionsUse PPRC for high value transactions Forward recovery Remote Recovery Data FacilityOther benefits of PPRC and XRC 236 CICS TS for z/OS 4.1 Recovery and Restart GuideAbout this task Choosing between RRDF and 3990-6 solutionsDisaster recovery personnel considerations RRDFReturning to your primary site Disaster recovery facilitiesMVS system logger recovery support 238 CICS TS for z/OS 4.1 Recovery and Restart GuideRemote site recovery for RLS-mode data sets CICS VSAM Recovery QSAM copyRemote Recovery Data Facility support CICS VR shadowingFinal summary Part 4. Appendixes Copyright IBM Corp. 1982242 CICS TS for z/OS 4.1 Recovery and Restart Guide Notices Trademarks 244 CICS TS for z/OS 4.1 Recovery and Restart GuideBibliography Access to CICSAdministration CICS books for CICS Transaction Server for z/OSOther CICS publications Administration and ManagementCICSPlex SM books for CICS Transaction Server for z/OS GeneralAccessibility 248 CICS TS for z/OS 4.1 Recovery and Restart Guide Index A DL/I continued files continuedlocking continued Page Recovery and Restart Guide Publication No. SC34-7012-01 Readers’ Comments - Wed Like to Hear from YouCICS Transaction Server for z/OS Version 4 Release SC34-7012-01 Readers’ Comments - Wed Like to Hear from YouSC34-7012-01 IBM United Kingdom LimitedPage SC34-7012-01