Cics TS for z/OS 4.1 Recovery and Restart Guide | IBM SC34-7012-01

222CICS 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

Contents

Recovery and Restart Guide Page Recovery and Restart Guide Copyright IBM Corporation 1982 Contents Part 3. Implementing recovery Restart Programming for recovery 141 Disaster recovery 223 Part 4. Appendixes 241 What this book is about How to use this bookPreface Who should read this book Viii Cics TS for z/OS 4.1 Recovery and Restart Guide Copyright IBM Corp Cics TS for z/OS 4.1 Recovery and Restart Guide Part 1. Cics recovery and restart concepts Cics TS for z/OS 4.1 Recovery and Restart Guide Recovery and restart facilities Maintaining the integrity of dataLogging changes Minimizing the effect of failures Role of Cics Recoverable resources Cics backward recovery backout Dynamic transaction backout Emergency restart backout Cics forward recovery Forward recovery of Cics data sets Failures that require Cics recovery processing Cics recovery processing following a communication failureForward recovery for non-VSAM resources XCF/MRO partner failures Cics recovery processing following a transaction failure Cics recovery processing following a system failure Recovery and restart facilities Cics TS for z/OS 4.1 Recovery and Restart Guide Resource recovery in Cics Units of workShunted units of work Locks Active and retained states for locks Synchronization points Examples of synchronization points Units of work and syncpoints Cics recovery manager Backout of units of work DB2 Coordinating updates to local resources Coordinating updates in distributed units of work Managing indoubt units of work Resynchronization after system or connection failure Cics system logInformation recorded on the system log Forward recovery logs System activity keypointsUser journals and automatic journaling Resource recovery in Cics Cics TS for z/OS 4.1 Recovery and Restart Guide Shutdown and restart recovery Normal shutdown processingFirst quiesce stage Second quiesce stage Third quiesce stage Warm keypoints Shunted units of work at shutdown Flushing journal buffers Immediate shutdown processing Perform Shutdown ImmediatePerform Immediate not recommended Shutdown requested by the operating system Dfhcesd Uncontrolled termination Shutdown assist transaction Cataloging Cics resources Global catalog Local catalog Effect of problems with the system log Shutdown initiated by Cics log manager How the state of the Cics region is reconstructed DFHRM0403 and DFHRM0404 Emergency restart Overriding the type of start indicatorWarm restart About this task Recovery of data during an emergency restart Cold startAn initial start of Cics Dynamic RLS restart SNPS, single-node persistent sessions Recovery with Vtam persistent sessionsRunning with persistent sessions support MNPS, multinode persistent sessions Situations in which sessions are not reestablished Running without persistent sessions support Situations in which Vtam does not retain sessions Regions that do have persistent sessions support Cics TS for z/OS 4.1 Recovery and Restart Guide Part 2. Recovery and restart processes Cics TS for z/OS 4.1 Recovery and Restart Guide Cics cold start Starting Cics with the START=COLD parameter Files Vsam Temporary storage data sharing server Temporary storageTransient data Data tables Journal names and journal models Resource definitions dynamically installedTransactions Library resources Committing and cataloging resources installed from the CSD Monitoring and statisticsTerminal control resources Dump table Installable set installDistributed transaction resources Starting Cics with the START=INITIAL parameter Cics cold start Cics TS for z/OS 4.1 Recovery and Restart Guide Cics warm restart Rebuilding the Cics state after a normal shutdown Reconnecting to Smsvsam for RLS access Data set name blocksRecreating non-RLS retained locks TDINTRA=NOEMPTY the default Trigger levels for Terminal and System only No autoinstall for programs Autoinstall for programs Start requests CSD-defined resource definitions Tcam and sequential Bsam devices Urimap definitions and virtual hosts Cics TS for z/OS 4.1 Recovery and Restart Guide Cics emergency restart Recovering after a Cics failureRecovering information from the system log Driving backout processing for in-flight units of work Effect of delayed recovery on Pltpi processing Other backout processingRebuilding the Cics state after an abnormal termination Reconnecting to Smsvsam for RLS access RLS restart processing and orphan locksRecreating non-RLS retained locks Start requests Distributed transaction resources Cics TS for z/OS 4.1 Recovery and Restart Guide Automatic restart management Cics ARM processingRestrictions De-registering from ARM Registering with ARMWaiting for predecessor subsystems Before you begin Failing to register ARM couple data setsCics restart JCL and parameters Connecting to Vtam Workload policiesCics Start options Automatic restart of Cics data-sharing servers Covr transactionMessages associated with automatic restart Server ARM processing Server initialization parameters for ARM support Server commands for ARM supportWaiting on events during initialization ARMELEMENTNAME=elementname In-flight-failed Unit of work recovery and abend processingUnit of work recovery Commit-failed Transaction backout Backout-failedIndoubt-failed Files Bdam files and Vsam Esds filesCics data tables Intrapartition transient data Auxiliary temporary storageStart requests Start with nonrecoverable data Protect Start with recoverable data ProtectStart with nonrecoverable data no Protect Restart of started transactions Exec Cics Cancel requests Basic mapping support BMS messages Backout-failed recovery Retrying backout-failed units of work ErrorTransient data Disposition of data sets after backout failures Open error Logical delete not performedSmsvsam server failure Smsvsam server recycle during backout DFSMSdss non-BWO backup in progressDuplicate key error Coupling facility cache structure failure Commit-failed recovery Lock structure full errorNone of the above Indoubt failure recovery Investigating an indoubt failure Cemt Inquire UOW details of UOW AC0CD65E5D990800 Cemt Inquire UOWENQ-details of a lock associated with a UOW Recovery from failures associated with the coupling facility Cache failure support Lost locks recovery Rebuilding the lock structureNotifying Cics of Smsvsam restart Performing lost locks recovery for failed units of work MVS system recovery and sysplex recovery Connection failure to a coupling facility cache structureConnection failure to a coupling facility lock structure Transaction abend processing Exit code Abnormal termination of a task Transaction restart Actions taken at transaction failure Processing operating system abends and program checks Unit of work recovery and abend processing Cics TS for z/OS 4.1 Recovery and Restart Guide Node error program Dfhznep Communication error processingTerminal error processing Terminal error program Dfhtep Intersystem communication failures Part 3. Implementing recovery and restart Cics TS for z/OS 4.1 Recovery and Restart Guide Planning aspects of recovery Questions relating to recovery requirementsApplication design considerations Validate the recovery requirements statement Designing the end user’s restart procedure End user’s standby proceduresCommunications between application and user Resource definitions for recovery System definitions for recovery-related functionsSystem recovery table SRT Security Temporary storage table Documentation and test plansTransient data queues Program list table PLT Cics TS for z/OS 4.1 Recovery and Restart Guide Defining system and general log streams System log streams Defining log streams to MVSDefining system log streams General log streams Specifying a Journalmodel resource definition Without a Journalmodel definitionWith a Journalmodel definition Recovery considerations Model log streams for Cics system logs Sharing system logger structures between 2 MVS images Activity keypointing Varying the model log stream nameAbout this task Keeping system log data to a minimum System log scan during restart Log-tail deletion Moving units of work to the secondary log Writing user-recovery data Avoiding retention periods on the system logRetrieving user records from the system log Defining forward recovery log streams About this task ProcedureLong-running transactions Model log streams for Cics general logs What to do next Merging data on shared general log streams Defining the log of logs Log of logs failure Reading log streams offline Adjusting local time Effect of daylight saving time changesTime stamping log and journal records Offline utility program, Dfhjup Cics TS for z/OS 4.1 Recovery and Restart Guide Defining transaction recovery attributes Defining recoverability for CICS-managed resourcesRecovery for transactions DTIMOUTNO1-6800 Indoubt options for distributed transactions WAITTIME00,00,00dd,hh,mm Vsam files Recovery for filesFile-owning regions and RLS access Sharing data sets with batch jobs Forward recovery Basic direct access method BdamDefining files as recoverable resources Backward recovery Vsam files accessed in non-RLS mode Recoveryall Vsam files accessed in RLS mode Inquiring on recovery attributes CSD data set File recovery attribute consistency checking non-RLSBdam files Overriding open failures at the Xfcnrec global user exit Cics responses to file open requests Recovery for intrapartition transient data Implementing forward recovery with user-written utilitiesImplementing forward recovery with Cics Vsam Recovery Backward recovery Logical recovery Physical recovery Forward recovery No recovery Recovery for extrapartition transient data Input extrapartition data sets Using post-initialization Pltpi programs Recovery for temporary storageOutput extrapartition data sets Recovery for Web services Configuring Cics to support persistent messages Defining local queues in a service provider Results What to do next Error processing Persistent message processing Defining recoverability for CICS-managed resources Cics TS for z/OS 4.1 Recovery and Restart Guide Programming for recovery Designing applications for recoverySplitting the application into transactions Cics TS for z/OS 4.1 Recovery and Restart Guide SAA-compatible applications Program designDividing transactions into units of work Processing dialogs with users Conversational processingPseudoconversational processing Cics recoverable resources Mechanisms for passing data between transactionsMain storage areas Designing to avoid transaction deadlocks Implications of interval control Start requests Using transient data queues Implications of automatic task initiation TD trigger levelTerminal paging through BMS Managing transaction and system failures Transaction failures Handle Abend commands Exec Cics Syncpoint Rollback commandDynamic transaction backout Handling abends and program level abend exits Use of the program error program DfhpepSystem failures Transaction restart after DTB Command Information provided Processing the Ioerr condition Start Transid commands PL/I programs and error handlingLocking enqueuing on resources in application programs Nonrecoverable files Implicit locking for files Recoverable files Cics TS for z/OS 4.1 Recovery and Restart Guide Implicit enqueuing on logically recoverable TD destinations Implicit enqueuing on recoverable temporary storage queuesWriteq TD Readq TD Deleteq TD Direct methods HDAM, Hidam Implicit enqueuing on DL/I databases with DbctlExplicit enqueuing by the application programmer Sequential methods HSAM, HISAM, Shisam Possibility of transaction deadlock Deadlock Where you can add your own code User exits for transaction backout Xrcinit exit Xrcinpt exitXfcbfail global user exit Xfcbout global user exit Xfcldel global user exitXfcbover global user exit Coding transaction backout exits Using a program error program PEP CICS-supplied PEP Your own PEP Omitting the PEP Cics TS for z/OS 4.1 Recovery and Restart Guide Resolving retained locks on recoverable resources Quiescing RLS data sets RLS quiesce and unquiesce functions Illustration of the quiesce flow across two Cics regions MVS1 MVS2 Cics AOR1 Cics AOR2 Non-BWO data set backup start Other quiesce interface functions BWO backup end Non-BWO data set backup endBWO backup start Forward recovery complete Exception for read-only operations Switching from RLS to non-RLS access modeLost locks recovery complete Quiesce coupling facility cache available What can prevent a switch to non-RLS access mode? Investigating which retained locks are held and why Inquire Dsname Shcds List subcommands Resolving retained locks and preserving data integrity Choosing data availability over data integrity Cemt command examples Batch-enabling sample programs Uowdsnfail Special case lost locks Permitnonrlsupdate subcommandDenynonrlsupdate subcommand Overriding retained locks Post-batch processing Coupling facility data table retained locks Moving recoverable data sets that have retained locks Procedure for moving a data set with retained locksUsing the Repro method Shcds Frsetrr Using the Export and Import functions Rebuilding alternate indexes Forward recovery procedures Forward recovery of data sets accessed in RLS mode Recovery of data set with volume still available Issue the Frresetrr subcommand Recovery of data set with loss of volumeIssue the Frbind subcommand Alter the new data set name Volume recovery procedure using Cfvol Quiesce Forward recovery procedures Example of recovery using data set backup Shcds LISTSUBSYSDS’ADSWA01D’ Vary SMS,SMSVSAM,FORCEDELETELOCKSTRUCTURE Inquire Uowdsnfail Status Results Example of recovery using volume backup Catalog recovery Above command produced the following message Forward recovery of data sets accessed in non-RLS mode Procedure for failed RLS mode forward recovery operationClose all files Forward recovery procedures Uowactioncommit Backout Force Procedure for failed non-RLS mode forward recovery operation Cics TS for z/OS 4.1 Recovery and Restart Guide Backup-while-open BWO BWO and backupsBWO and concurrent copy BWO requirements Component name Full DFSMS/MVS name Previous product Name Hardware requirements Which data sets are eligible for BWOVsam control interval or control area split Specifying BWO using access method services How you request BWOResults Specifying BWO on Cics file resource definitions Systems administration Removing BWO attributesBatch jobs BWO processing First file opened in non-RLS mode against a cluster File openingBack-level data sets Subsequent files opened when use count is not zero Subsequent files opened when use count is zero File closing non-RLS mode Restriction for Vsam upgrade set Controlled shutdown Data set backup and restoreShutdown and restart Immediate or uncontrolled shutdown Vsam access method services Invalid state changes for BWO attributes Data sets Forward recovery loggingData set restore Non-SMS managed storage Recovery point non-RLS mode Recovering Vsam spheres with AIXs An assembler program that calls Dfsms callable services ASM XOPTSCICS,NOEPILOG,SP DS 8C MVC MVC SUCMSG18,SUCTXT1 SUCMSG21,SUCTXT2 Cics TS for z/OS 4.1 Recovery and Restart Guide Disaster recovery Why have a disaster recovery plan? Disaster recovery testing Six tiers of solutions for off-site recovery Tier 0 no off-site dataTier 1 physical removal Disaster recovery tier 1 physical removal Tier 2 physical removal with hot site Tier 3 electronic vaultingTier Tier 0-3 solutions Summarizes the tier 3 solution Tier 4 active secondary site Tier 0 Disaster recovery tier 4 active secondary site Tier 5 two-site, two-phase commit Tier 6 minimal to zero data loss Summarizes the tier 6 solution Tier 4-6 solutions Tier 4 Disaster recovery and high availability Peer-to-peer remote copy Pprc and extended remote copy XRC Pprc or XRC? Use Pprc for high value transactions Remote Recovery Data Facility Other benefits of Pprc and XRC Choosing between Rrdf and 3990-6 solutions Disaster recovery personnel considerations Disaster recovery facilities MVS system logger recovery supportReturning to your primary site Remote site recovery for RLS-mode data sets Cics Vsam Recovery Qsam copyRemote Recovery Data Facility support Cics VR shadowing Final summary Part 4. Appendixes 241 Cics TS for z/OS 4.1 Recovery and Restart Guide 243 Trademarks Bibliography Cics books for Cics Transaction Server for z/OS Administration and Management CICSPlex SM books for Cics Transaction Server for z/OSOther Cics publications Accessibility Cics TS for z/OS 4.1 Recovery and Restart Guide Airdelay Index DL/I 251 Tpend Readers’ Comments Wed Like to Hear from You Readers’ Comments Wed Like to Hear from You Page SC34-7012-01