TROUBLESHOOTING ORACLE DATAGUARD ISSUES

Hello Everyone,

This article is in conjunction with my another article on Oracle Dataguard setup with standby database creation. If you have not checked it out yet please do and leave your thoughts in the comments below. Now to this article , where we will take a look at few errors which we may face during the setup process of Oracle Data Guard with their troubleshooting steps. Hope this article is helpful and gives you more insight into Oracle Data Guard. Please do like and share if you liked this article. All suggesions are welcome. Have a nice day!

Setting up Oracle Data Guard can sometimes lead to various errors. Here are some common issues and their solutions:

Network Configuration Issues -

• Error: TNS-12514: TNS:listener does not currently know of service requested in connect descriptor.
• Solution: Ensure that the listener.ora and tnsnames.ora files are correctly configured and the listener is started on both primary and standby servers.

Log File Issues -

• Error: ORA-00333: redo log read error block.
• Solution: Verify that the redo logs are correctly configured and accessible. Ensure that the standby redo logs are the same size as the primary redo logs.

Password File Issues -

• Error: ORA-16191: Primary log shipping client not logged on standby.
• Solution: Ensure that the password file is identical on both primary and standby servers. Use orapwd to create and copy the password file.

Configuration Parameter Issues -

• Error: ORA-01105: mount is incompatible with mounts by other instances.
• Solution: Check and match the db_name and db_unique_name parameters between the primary and standby databases. Ensure the log_archive_config parameter is correctly set.

Archive Log Issues -

• Error: ORA-16014: log 2 sequence# 55 not archived, no available destinations.
• Solution: Ensure that the log_archive_dest parameters are correctly set and the archive destinations are accessible and have enough space.

Data Guard Broker Issues -

• Error: DGMGRL-08100: failed to connect to the database.
• Solution: Verify that the DG_BROKER_START parameter is set to TRUE on both primary and standby databases. Ensure the database is accessible using the connect identifier.

Log Apply Services Issues -

• Error: ORA-16139: media recovery required.
• Solution: Perform media recovery on the standby database:

    RMAN> RECOVER DATABASE;        

Snapshot Standby Issues -

• Error: ORA-16792: unable to set LOG_ARCHIVE_DEST_2 parameter to 'location'.
• Solution: Ensure the standby database is not in snapshot standby mode. Convert it back to physical standby mode if necessary.

File Management Issues -

• Error: ORA-01157: cannot identify/lock data file string - see DBWR trace file.
• Solution: Ensure all data files and redo logs are correctly copied and accessible. Verify the db_file_name_convert and log_file_name_convert parameters are correctly set.

General Errors -

• Error: ORA-16766: Redo Apply is stopped.
• Solution: Start Redo Apply on the standby database:

ALTER DATABASE RECOVER MANAGED STANDBY DATABASE DISCONNECT FROM SESSION;        

Troubleshooting Tips -

• Check Alert Logs: Review the alert logs on both primary and standby databases for detailed error messages.
• Monitor with Data Guard Broker: Use DGMGRL to monitor and diagnose issues.

  DGMGRL> SHOW CONFIGURATION;        

  DGMGRL> SHOW DATABASE 'standby_db' STATUSREPORT;        

• Verify Network Connectivity: Ensure there are no network issues between the primary and standby databases.
• Consult Documentation: Oracle’s official documentation and support resources can provide additional guidance and troubleshooting steps.

By identifying and addressing these common issues, we can troubleshoot and resolve errors in Oracle Data Guard configuration. Please leave a like, comment if the article was helpful in any way. Feel free to share your thoughts in the comments.