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Chapter 17 Troubleshooting RMAN. Background. Authors thought this topic was often glazed over or not covered well Knew that every topic can’t be covered, that could be a very long list Tried to cover the most common types of RMAN issues. Sources of Information.
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Background • Authors thought this topic was often glazed over or not covered well • Knew that every topic can’t be covered, that could be a very long list • Tried to cover the most common types of RMAN issues
Sources of Information • Backup and recovery problems are stressful • Usually you can find somebody else who has already encountered the issue • Start at bottom of error stack and work your way up • Syntax issues are common • Check alert.log and trace files
Sources of Information (continued) • Ask for help • Search Oracle’s documentation • Use RMAN forum • Open a SR with Oracle • Enable output logging (Oracle Support will often request this)
Resolving Connection Issues • Common problem • Usually caused by not using an authenticated user • If using a password file, ensure correct username/password are being used • Attempt to connect to SQL*Plus to troubleshoot
Handling Disk Space Issues • Usually caused by running out of disk space • To correct: • Change location of the backup • Add disk space (if possible) • If using a FRA, either add space or move • Change retention policy • Delete old files
Dealing with RMAN-06059 Error • Common problem, occurs when RMAN doesn’t know where old archive redo log files are located • Due to switching from user managed to RMAN • Due to not using RMAN to delete old files • “loss of archived log compromises recoverability”... Yikes! RMAN> crosscheck archivelog all;
Terminating RMAN Processes • Sometimes necessary when backup or restore hangs • Try control + C • Manually kill process from operating system • Kill RMAN session from SQL*Plus • Query v$session_longops to see if the job is actually making progress
Diagnosing NLS Character Set Issues • ORA-12705 error • Sometimes caused by a mismatch between NLS character set on client and server • Sometimes caused by an erroneously set NLS-related operating system parameter SQL> select value from v$nls_parameters where parameter = 'NLS_CHARACTERSET';
Logging RMAN Output • Extremely helpful for debugging/diagnosing issues • From OS prompt: $ rman target / log=rman_output.log • From within RMAN: RMAN> spool log to rman_output.log RMAN> set echo on RMAN> backup database; RMAN> spool log off;
Viewing RMAN Command History • Use v$rman_output SQL> select sid, recid, output from v$rman_output order by recid; • Holds 32,768 rows
Enabling Debug Output • You can turn on debugging in several different ways: • From the OS prompt • When allocating a channel • When configuring a channel • From the RMAN command-line prompt
Enabling Debug Output • Enable all debugging $ rman target / debug=all log=rman_output.log • Enables debugging just for I/O activities: $ rman target / debug=io
Information Types of Debugging • io • sql • plsql • rcvman • rpc
Enabling Granular Time Reporting • Oracle Support will often recommend that you enable this before sending them output • Allows you to view down to the second when operations occurred • Authors recommend that you always enable this • Korn shell example: $ export NLS_DATE_FORMAT='dd-mon-yyyy hh24:mi:ss'
Working with Oracle Support • Some problems will require help from Oracle Support • To facilitate response: • Test case that illustrates step-by-step details to reproduce the problem • Complete RMAN script or command(s) that were run • Complete RMAN output log • Database alert.log file • Remote Diagnostic Agent (RDA) output (optional)
Resolving RMAN Compatibility Issues • Ideally, all databases and catalog will be at the same level • Reality, almost never the case • Most up to date source RMAN compatibility matrix information in MetaLink note 73431.1 • Checking the recovery catalog version (if using): SQL> select * from rcver;
Dealing with an ORA-19511 Error • Vexing issue • Caused by MML mis-configuration • Caused by incorrectly set OS variables • Work with your MML vendor to resolve • Check sbtio.log file
Dealing with an ORA-27211 Error • Vexing issue • Usually related to MML not being correctly installed • Work with MML vendor to resolve • Look in log and trace files for more information
Dealing with an ORA-04031 Error • Enabled I/O slaves • RMAN will throw this if it can’t allocate enough memory • Setup a large pool area • Use ASMM • See MetaLink note 73354.1
Managing Files in an ASM Environment • Background: Technical editor wrote this material in the book, often received questions regarding ASM at Oracle Support • Using ASM (Automatic Storage Management) • Need to view RMAN files • Use ASMCMD • Command line utility $ asmcmd –p • Unix like commands