How to Disable Oracle Archive Logging

In Oracle databases, archive logging ensures that redo logs are archived, minimizing the risk of data loss. However, there are scenarios where you might need to disable this feature, such as:

• Optimizing performance in non-critical environments,
• Reducing disk space usage in development or test setups,
• Modifying backup strategies.

This guide walks you through the process of disabling Oracle archive logging using SQLPlus and explains the considerations to keep in mind.

What is Archive Logging, and Why Disable It?

Archive logging in Oracle determines whether the database operates in ARCHIVELOG mode. In this mode, redo log files are archived, supporting backup and recovery operations.

Advantages:

• Prevents data loss.
• Crucial for disaster recovery.

Disadvantages:

• Increases disk space usage.
• May impact performance, especially under heavy workloads.

If your environment doesn’t require archived logs (e.g., development or testing), disabling archive logging can be a suitable option.

Steps to Disable Archive Logging

1. Connect to SQLPlus

You need to log in with sysdba privileges to perform administrative tasks on the database.

SQL> conn sys as sysdba

2. Stop Archive Logging

The following command temporarily stops the archiving process.

SQL> alter system archive log stop;

3. Shutdown the Database

Safely shut down the database with the following command:

SQL> shutdown immediate

4. Start the Database in Exclusive Mount Mode

Start the database in mount restrict mode to perform administrative tasks.

SQL> startup mount restrict

5. Disable Archive Logging and Open the Database

Disable the archive log mode with the following commands:

SQL> alter database noarchivelog;
SQL> alter database open;

6. Verify Archive Logging is Disabled

Check the status of the archive logging mode:

SQL> archive log list

You should see output similar to this:

Database log mode            NOARCHIVELOG
Automatic archival           DISABLED
Archive destination          /mount_point/oradata/SID/ARCHIVE/arch
Oldest online log sequence   2
Current log sequence         3

The presence of “NOARCHIVELOG” and “DISABLED” confirms that the process was successful.

7. Restart the Database in Normal Mode

Finally, restart the database in normal mode:

SQL> shutdown immediate
SQL> startup

Key Considerations

1. Backup Strategy:
   Before disabling archive logging, review your backup plan. Databases in NOARCHIVELOG mode can only be backed up using cold backups, which require the database to be offline.
2. Performance Gains:
   Disabling archive logging can reduce disk I/O load and improve performance in non-critical environments.
3. Recovery Limitations:
   Without archive logging, recovery options are limited to the most recent full backup, which can lead to significant data loss in critical systems.

Alternatives to Disabling Archive Logging

If you prefer not to disable archive logging but still want to optimize performance, consider the following:

1. Increase Redo Log File Size: Larger log files reduce the frequency of log switches.
2. Optimize Disk Configuration: Store archive logs on high-speed storage for better performance.
3. Use Flashback Features: These can enhance recovery options without archive logging.

Conclusion

Disabling Oracle archive logging is an effective way to reduce disk usage and improve performance in non-critical environments like development and testing. However, it’s a step that requires careful planning, especially concerning backup and recovery strategies.