Introduction:
Enable Archive Log Mode in Oracle 12c and above is a crucial step to ensure data integrity, disaster recovery, and point-in-time recovery capabilities for your database. In this comprehensive guide, we’ll walk you through the process of enabling Archive Log Mode in Oracle 12c and above, providing step-by-step instructions and valuable insights to help you successfully configure this important feature.
Table of Contents:
- Understanding Archive Log Mode
- Preparing for Enabling Archive Log Mode
- Enabling Archive Log Mode
- Verifying Archive Log Mode Status
- Importance of Regular Archiving
- Conclusion
1. Understanding Archive Log Mode:
Archive Log Mode is a database feature that allows Oracle to generate archived redo logs, preserving a history of changes made to the database. This feature is essential for data recovery and helps in maintaining a comprehensive log of transactions.
2. Preparing for Enabling Archive Log Mode:
- Backup: Before making any significant changes, it’s advisable to perform a full database backup to ensure you have a stable starting point for recovery if needed.
- Check Space: Ensure that there is enough disk space available for storing archived redo logs.
- Database Shutdown: Make sure the database is in a consistent state by shutting it down properly.
Use below command to shut down the database:
SQL> shut immediate;3. Enabling Archive Log Mode:
- Connect as SYSDBA: Log in to the database as a user with SYSDBA privileges using SQL*Plus or any preferred database management tool.
- Start database in Mount stage: To enable archive log mode we need to start the DB in mount stage.
- Check Current Mode: Run the (b) SQL query to check the current database mode:
a) Start the DB in Mount stage after shutting down:
SQL> Startup mount;b) Check Log mode with below command:
SQL>SELECT log_mode FROM v$database;c) Switch to Archive Log Mode:
If the current mode is "NOARCHIVELOG," you can switch to Archive Log Mode using the following command:
SQL>ALTER DATABASE ARCHIVELOG;d) Open the Database:
Once the database is in Archive Log Mode, open it using:
SQL>ALTER DATABASE OPEN;4.Verifying Archive Log Mode Status:
To confirm that the database is now in Archive Log Mode, run the query mentioned in step 3 again (b). The output should now indicate “ARCHIVELOG“ as the log mode.
5. Importance of Regular Archiving:
Regularly backing up and archiving redo logs is crucial for maintaining a point-in-time recovery option. These archived logs serve as a record of all changes made to the database, enabling you to recover the database to a specific moment in time.
6. Conclusion:
Enabling Archive Log Mode in Oracle 12c and above is an essential step for ensuring data integrity and enabling effective disaster recovery strategies. By following the steps outlined in this guide, you can successfully configure Archive Log Mode and take a significant stride towards maintaining a robust and recoverable database environment.
Remember to always consult the official Oracle documentation for the most up-to-date and accurate information on managing your Oracle database.