RDS Custom

Understanding the Limitations

By default, traditional RDS does not grant access to the underlying OS, which can be limiting for cases that require customization.


RDS Custom is a specialized service within AWS that provides managed Oracle and Microsoft SQL Server databases with a unique twist – it allows for operating system (OS) and database customization. While traditional RDS automates the setup, operation, and scaling of databases in AWS, RDS Custom goes a step further by giving you direct access to the underlying database and OS.

Key Features

  1. Configuration Control: With RDS Custom, you have the power to configure settings, install patches, and enable native features according to your specific requirements.

  2. Access to EC2 Instances: Gain access to the underlying EC2 instance using SSH or SSM Session Manager for a more hands-on approach.

  3. Automation Mode: While in Automation Mode, you can deactivate it temporarily to perform your customizations. It's advisable to take a DB snapshot before making significant changes.

RDS vs. RDS Custom

  • RDS: In standard RDS, AWS manages both the entire database and the operating system.
  • RDS Custom: With RDS Custom, you get full admin access to both the underlying OS and the database, offering a higher level of customization.

Benefits of RDS Custom

1. Third-Party Applications

  • Installations: RDS Custom allows you to install third-party applications directly onto your managed database.

2. Legacy Application Support

  • File System Modification: Modify file systems to support legacy applications, providing flexibility in your database environment.

3. Custom Patches

  • Database and OS: Apply custom patches to your database or modify OS packages, ensuring your RDS Custom DB instances meet your specific needs.


RDS Custom caters to users who require a higher degree of control and customization over their database environment. Supported for Oracle and Microsoft SQL Server, it opens up possibilities for a more tailored and flexible AWS database experience.