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

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52CICS TS for z/OS 4.1: Recovery and Restart Guide

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

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Recovery and Restart Guide CICS Transaction Server for z/OSVersion 4 Release SC34-7012-01Page Recovery and Restart Guide CICS Transaction Server for z/OSVersion 4 Release SC34-7012-01Copyright IBM Corporation 1982 Contents Part 1. CICS recovery and restart conceptsPart 2. Recovery and restart processes Chapter 2. Resource recovery in CICSPart 3. Implementing recovery and Chapter 9. Communication errorrecovery Chapter 8. Unit of work recovery andChapter 13. Programming for recovery Chapter 16. Moving recoverable dataChapter 17. Forward recovery Chapter 18. Backup-while-open BWOChapter 19. Disaster recovery AccessibilityPart 4. Appendixes NoticesHow to use this book PrefaceWhat this book is about 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 locksSynchronization points EXEC CICS CREATE TERMINAL EXEC CICS CREATE CONNECTION COMPLETEEXEC CICS DISCARD CONNECTION EXEC CICS DISCARD TERMINAL EXEC CICS CREATE TERMINALEXEC CICS CREATE CONNECTION COMPLETE EXEC CICS DISCARD CONNECTION Examples of synchronization pointsEXEC CICS DISCARD TERMINAL CICS recovery manager FC/RLS Recoveryv Coordinating recoverable conversations to remote nodes 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 managerHow the state of the CICS region is reconstructed DFHRM0402DFHRM0403 and DFHRM0404 DFHRM0405Overriding the type of start indicator Warm restartEmergency restart About this taskCold start Recovery of data during an emergency restartAn initial start of CICS Dynamic RLS restart Recovery with VTAM persistent sessions Running with persistent sessions supportSNPS, single-node persistent sessions 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 Transient dataTemporary storage data sharing server Data tablesResource definitions dynamically installed TransactionsJournal names and journal models LIBRARY resourcesCommitting and cataloging resources installed from the CSD Single resource installMonitoring and statistics Terminal control resourcesInstallable set install Distributed transaction resourcesDump table 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 shutdownReconnecting to SMSVSAM for RLS access Data set name blocksRecreating non-RLS retained locks FilesTDINTRA=NOEMPTY the default TDINTRA=EMPTYTrigger levels for TERMINAL and SYSTEM only Temporary storageNo autoinstall for programs TransactionsLIBRARY resources ProgramsStart requests Autoinstall for programsMonitoring and statistics CSD-defined resource definitions TCAM and sequential BSAM devicesJournal names and journal models 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 Recovering after a CICS failure Recovering information from the system logChapter 6. CICS emergency restart Driving backout processing for in-flight units of workEffect of delayed recovery on PLTPI processing Other backout processingRebuilding the CICS state after an abnormal termination 62 CICS TS for z/OS 4.1 Recovery and Restart GuideReconnecting to SMSVSAM for RLS access RLS restart processing and orphan locksRecreating non-RLS retained locks Temporary storage64 CICS TS for z/OS 4.1 Recovery and Restart Guide Start requestsTerminal control resources 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 Registering with ARM Waiting for predecessor subsystemsDe-registering from ARM Before you beginFailing to register ARM couple data setsCICS restart JCL and parameters Chapter 7. Automatic restart managementWorkload policies Connecting to VTAMCICS START options The COVR transaction Messages associated with automatic restartAutomatic restart of CICS data-sharing servers Server ARM processingServer commands for ARM support CANCEL RESTART=NOYESWaiting on events during initialization Server initialization parameters for ARM supportChapter 8. Unit of work recovery and abend processing Unit of work recoveryIn-flight-failed Commit-failedBackout-failed Transaction backoutIndoubt-failed BDAM files and VSAM ESDS files FilesCICS data tables START with recoverable data no PROTECT Intrapartition transient dataAuxiliary temporary storage START requestsSTART with recoverable data PROTECT START with nonrecoverable data no PROTECTSTART with nonrecoverable data PROTECT Restart of started transactionsBasic mapping support BMS messages EXEC CICS CANCEL requestsBackout-failed recovery Auxiliary temporary storageI/O error Transient dataRetrying backout-failed units of work Disposition of data sets after backout failuresLogical delete not performed Open errorSMSVSAM server failure DFSMSdss non-BWO backup in progress Duplicate key errorSMSVSAM server recycle during backout 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 supportLost locks recovery Rebuilding the lock structureNotifying CICS of SMSVSAM restart 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 Chapter 9. Communication error processing Terminal error processingNode error program DFHZNEP 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 Designing the end user’s restart procedure End user’s standby proceduresCommunications between application and user About this taskSystem definitions for recovery-related functions System recovery table SRTResource definitions for recovery SecurityDocumentation and test plans Transient data queuesTemporary storage table Program list table PLTv Forecast the exceptional conditions that can be expected recovery purposes only Forward recovery loggingChapter 11. Defining system and general log streams System loggingDefining log streams to MVS Defining system log streamsSystem 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 Writing user-recovery data Avoiding retention periods on the system logRetrieving user records from the system log About this taskDefining forward recovery log streams About this task ProcedureLong-running transactions 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 Log of logs failure Reading log streams offlineAbout this task About this taskAdjusting local time Effect of daylight saving time changesTime stamping log and journal records About this taskOffline utility program, DFHJUP 122 CICS TS for z/OS 4.1 Recovery and Restart Guide Chapter 12. Defining recoverability for CICS-managed resources Recovery for transactionsDefining transaction recovery attributes RESTARTNOYESIndoubt options for distributed transactions SPURGENOYESTPURGENOYES ACTIONBACKOUTCOMMITRecovery for files File-owning regions and RLS accessVSAM files Sharing data sets with batch jobsBasic direct access method BDAM Defining files as recoverable resourcesForward recovery Backward recoveryVSAM files accessed in non-RLS mode RECOVERYALLRECOVERYBACKOUTONLY BACKUPTYPEDYNAMICVSAM files accessed in RLS mode Inquiring on recovery attributesLOGNONEUNDOALL NONEFile recovery attribute consistency checking non-RLS BDAM filesThe CSD data set Overriding open failures at the XFCNREC global user exitCICS responses to file open requests About this taskImplementing forward recovery with user-written utilities Implementing forward recovery with CICS VSAM Recovery MVS/ESARecovery for intrapartition transient data Backward recoveryLogical recovery Physical recoveryForward recovery No recoveryRecovery for extrapartition transient data Input extrapartition data setsUsing post-initialization PLTPI programs Recovery for temporary storageOutput extrapartition data sets Backward recoveryRecovery for Web services Configuring CICS to support persistent messagesForward recovery GROUPTSRECOV PREFIXDF LOCATIONAUXILIARY RECOVERYYESDefining local queues in a service provider ProcedureResults What to do next ProcedureError processing Persistent message processingFor example, your recovery transaction could 140 CICS TS for z/OS 4.1 Recovery and Restart Guide Chapter 13. Programming for recovery Designing applications for recoverySplitting the application into transactions About this task ProcedureExample What to do next Relationships between processing units 142 CICS TS for z/OS 4.1 Recovery and Restart GuideSAA-compatible applications Program designDividing transactions into units of work ProcedureConversational processing Processing dialogs with usersPseudoconversational processing Mechanisms for passing data between transactions CICS recoverable resourcesMain storage areas Designing to avoid transaction deadlocks Temporary storage auxiliaryTransient data queues User files and DL/I and DB2 databasesImplications of interval control START requests ProcedureUsing transient data queues Implications of automatic task initiation TD trigger levelImplications of presenting large amounts of data to the user Terminal paging through BMSManaging transaction and system failures Transaction failuresAbout this task About this taskEXEC CICS SYNCPOINT ROLLBACK command HANDLE ABEND commandsDynamic transaction backout Use of the program error program DFHPEP System failuresHandling abends and program level abend exits 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 Implicit enqueuing on DL/I databases with DBCTL Explicit enqueuing by the application programmerDirect methods HDAM, HIDAM Sequential methods HSAM, HISAM, SHISAMPossibility of transaction deadlock deadlockUser exits for transaction backout Where you can add your own codeAbout this task XRCINIT exit XRCINPT exitXFCBFAIL global user exit ProcedureXFCLDEL global user exit XFCBOVER global user exitXFCBOUT global user exit Coding transaction backout exitsChapter 14. Using a program error program PEP The CICS-supplied PEPProcedure 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 Chapter 15. Resolving retained locks on recoverable resources Quiescing RLS data setsAbout this task 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 functionsNon-BWO data set backup end BWO backup startBWO backup end Forward recovery completeSwitching from RLS to non-RLS access mode Lost locks recovery completeException for read-only operations Quiesce coupling facility cache availableWhat can prevent a switch to non-RLS access mode? Resolving retained locks before opening data sets in non-RLS mode Investigating which retained locks are held and whyProcedure About this taskINQUIRE UOWDSNFAIL INQUIRE DSNAMEAbout this task SHCDS LIST subcommands Resolving retained locks and preserving data integrityAbout this task Procedure 176 CICS TS for z/OS 4.1 Recovery and Restart GuideChoosing data availability over data integrity About this taskCEMT command examples The batch-enabling sample programsDFH0BAT1 DFH0BAT2SET DSNAME’RLS.ACCOUNTS.ESDS.DBASE1’ RETRY STATUS RESULTS - OVERTYPE TO MODIFYDsnRLS.ACCOUNTS.ESDS.DBASE1 NORMALThe PERMITNONRLSUPDATE subcommand The DENYNONRLSUPDATE subcommandA special case lost locks Overriding retained locksPost-batch processing Coupling facility data table retained locks Chapter 16. Moving recoverable data sets that have retained locks Procedure for moving a data set with retained locksUsing the REPRO method About this taskSHCDS FRRESETRR SHCDS FRSETRRSHCDS FRUNBIND 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 Recovery of data set with volume still available 3. Issue FRSETRR4. Issue FRUNBIND 5. Restore the backupRecovery of data set with loss of volume 10. Issue the FRBIND subcommand11. Issue the FRRESETRR 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 Forward recovery of data sets accessed in non-RLS mode Procedure for failed RLS mode forward recovery operation3. Restore the backup 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 BWO requirements Component nameFull DFSMS/MVS name Previous productWhich data sets are eligible for BWO Hardware requirementsVSAM control interval or control area split Specifying BWO using access method services How you request BWOResults TYPECICSSpecifying BWO on CICS file resource definitions About this taskSystems administration Removing BWO attributesBatch jobs 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 setData set backup and restore Shutdown and restartControlled shutdown Immediate or uncontrolled shutdownVSAM access method services Invalid state changes for BWO attributesForward recovery logging Data set restoreData sets Non-SMS managed storageRecovery point non-RLS mode Forward recoveryRecovering VSAM spheres with AIXs About this taskAn assembler program that calls DFSMS callable services DATETIME DTTENTHSRECOVPTP DATEPACK220 CICS TS for z/OS 4.1 Recovery and Restart Guide PRGCONTBWOFLAGS12,ZEROES 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 Remote Recovery Data Facility Other benefits of PPRC and XRCForward recovery 236 CICS TS for z/OS 4.1 Recovery and Restart GuideChoosing between RRDF and 3990-6 solutions Disaster recovery personnel considerationsAbout this task RRDFDisaster recovery facilities MVS system logger recovery supportReturning to your primary site 238 CICS TS for z/OS 4.1 Recovery and Restart GuideCICS VSAM Recovery QSAM copy Remote Recovery Data Facility supportRemote site recovery for RLS-mode data sets 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 GuideAccess to CICS AdministrationBibliography CICS books for CICS Transaction Server for z/OSAdministration and Management CICSPlex SM books for CICS Transaction Server for z/OSOther CICS publications 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 Readers’ Comments - Wed Like to Hear from You SC34-7012-01SC34-7012-01 IBM United Kingdom LimitedPage SC34-7012-01