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

242CICS 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 Logging changes Recovery and restart facilitiesMaintaining the integrity of data 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 Forward recovery for non-VSAM resources Failures that require Cics recovery processingCics recovery processing following a communication failure 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 Shunted units of work Resource recovery in CicsUnits 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 Information recorded on the system log Resynchronization after system or connection failureCics system log User journals and automatic journaling Forward recovery logsSystem activity keypoints Resource recovery in Cics Cics TS for z/OS 4.1 Recovery and Restart Guide First quiesce stage Shutdown and restart recoveryNormal shutdown processing Second quiesce stage Third quiesce stage Warm keypoints Shunted units of work at shutdown Perform Immediate not recommended Flushing journal buffersImmediate shutdown processing Perform Shutdown Immediate 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 An initial start of Cics Recovery of data during an emergency restartCold start 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 Terminal control resources Committing and cataloging resources installed from the CSDMonitoring and statistics 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 Recreating non-RLS retained locks Reconnecting to Smsvsam for RLS accessData set name blocks 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 Rebuilding the Cics state after an abnormal termination Effect of delayed recovery on Pltpi processingOther backout processing Recreating non-RLS retained locks Reconnecting to Smsvsam for RLS accessRLS restart processing and orphan locks Start requests Distributed transaction resources Cics TS for z/OS 4.1 Recovery and Restart Guide Restrictions Automatic restart managementCics ARM processing De-registering from ARM Registering with ARMWaiting for predecessor subsystems Before you begin Cics restart JCL and parameters Failing to registerARM couple data sets Cics Start options Connecting to VtamWorkload policies 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 Indoubt-failed Transaction backoutBackout-failed Cics data tables FilesBdam files and Vsam Esds files Start requests Intrapartition transient dataAuxiliary temporary storage 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 Smsvsam server failure Open errorLogical delete not performed Smsvsam server recycle during backout DFSMSdss non-BWO backup in progressDuplicate key error Coupling facility cache structure failure None of the above Commit-failed recoveryLock structure full error 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 Notifying Cics of Smsvsam restart Lost locks recoveryRebuilding the lock structure Performing lost locks recovery for failed units of work Connection failure to a coupling facility lock structure MVS system recovery and sysplex recoveryConnection failure to a coupling facility cache 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 Application design considerations Planning aspects of recoveryQuestions relating to recovery requirements Validate the recovery requirements statement Communications between application and user Designing the end user’s restart procedureEnd user’s standby procedures 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 With a Journalmodel definition Specifying a Journalmodel resource definitionWithout a Journalmodel definition Recovery considerations Model log streams for Cics system logs Sharing system logger structures between 2 MVS images About this task Activity keypointingVarying the model log stream name Keeping system log data to a minimum System log scan during restart Log-tail deletion Moving units of work to the secondary log Retrieving user records from the system log Writing user-recovery dataAvoiding retention periods on the system log Long-running transactions Defining forward recovery log streamsAbout this task Procedure 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 Time stamping log and journal records Adjusting local timeEffect of daylight saving time changes 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 Output extrapartition data sets Using post-initialization Pltpi programsRecovery for temporary storage 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 Splitting the application into transactions Programming for recoveryDesigning applications for recovery Cics TS for z/OS 4.1 Recovery and Restart Guide Dividing transactions into units of work SAA-compatible applicationsProgram design Pseudoconversational processing Processing dialogs with usersConversational processing Main storage areas Cics recoverable resourcesMechanisms for passing data between transactions Designing to avoid transaction deadlocks Implications of interval control Start requests Terminal paging through BMS Using transient data queuesImplications of automatic task initiation TD trigger level Managing transaction and system failures Transaction failures Dynamic transaction backout Handle Abend commandsExec Cics Syncpoint Rollback command 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 Locking enqueuing on resources in application programs Start Transid commandsPL/I programs and error handling Nonrecoverable files Implicit locking for files Recoverable files Cics TS for z/OS 4.1 Recovery and Restart Guide Writeq TD Readq TD Deleteq TD Implicit enqueuing on logically recoverable TD destinationsImplicit enqueuing on recoverable temporary storage queues 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 Xfcbfail global user exit Xrcinit exitXrcinpt 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 Using the Repro method Moving recoverable data sets that have retained locksProcedure for moving a data set with retained locks 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 Close all files Forward recovery of data sets accessed in non-RLS modeProcedure for failed RLS mode forward recovery operation 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 BWO and concurrent copy Backup-while-open BWOBWO and backups BWO requirements Component name Full DFSMS/MVS name Previous product Name Vsam control interval or control area split Hardware requirementsWhich data sets are eligible for BWO Results Specifying BWO using access method servicesHow you request BWO Specifying BWO on Cics file resource definitions Batch jobs Systems administrationRemoving BWO attributes BWO processing Back-level data sets First file opened in non-RLS mode against a clusterFile opening 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 Tier 1 physical removal Six tiers of solutions for off-site recoveryTier 0 no off-site data Disaster recovery tier 1 physical removal Tier Tier 2 physical removal with hot siteTier 3 electronic vaulting 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 Returning to your primary site Disaster recovery facilitiesMVS system logger recovery support 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 Other Cics publications Administration and ManagementCICSPlex SM books for Cics Transaction Server for z/OS 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