Managing Exadata DB System I/O Resources

This topic explains the I/O Resource Management (IORM) feature and how to enable it, modify the IORM settings, and disable it by using the Console or the API.

About IORM

The I/O Resource Management (IORM) feature allows you to manage how multiple databases share the I/O resources of an Oracle Exadata DB system.

On an Exadata DB system, all databases share dedicated storage servers which include flash storage. By default, the databases are given equal priority with respect to these resources. The Exadata storage management software uses a first come, first served approach for query processing. If a database executes a major query that overloads I/O resources, overall system performance can be slowed down.

IORM allows you to assign priorities to your databases to ensure critical queries are processed first when workloads exceed their resource allocations. You assign priorities by creating directives that specify the number of shares for each database. The number of shares corresponds to a percentage of resources given to that database when I/O resources are stressed.

Directives work together with an overall optimization objective you set for managing the resources. The following objectives are available:

  • Auto - Recommended. IORM determines the optimization objective and continuously and dynamically determines the optimal settings, based on the workloads observed, and resource plans enabled.
  • Balanced - For critical OLTP and DSS workloads. This setting balances low disk latency and high throughput. This setting limits disk utilization of large I/Os to a lesser extent than low latency to achieve a balance between good latency and good throughput.
  • High throughput - For critical DSS workloads that require high throughput.
  • Low latency - For critical OLTP workloads. This setting provides the lowest possible latency by significantly limiting disk utilization.

For more information about IORM, see Exadata System Software User's Guide.

Required IAM Policy

To use Oracle Cloud Infrastructure, you must be given the required type of access in a policy  written by an administrator, whether you're using the Console or the REST API with an SDK, CLI, or other tool. If you try to perform an action and get a message that you don’t have permission or are unauthorized, confirm with your administrator the type of access you've been granted and which compartment  you should work in.

For administrators: The policy in Let database admins manage DB systems lets the specified group do everything with databases and related Database resources.

If you're new to policies, see Getting Started with Policies and Common Policies. If you want to dig deeper into writing policies for databases, see Details for the Database Service.

Using the Console

To enable IORM on your Exadata DB system

Enabling IORM includes specifying an optimization objective and configuring your resource plan directives.

  1. Open the navigation menu. Under Database, click Bare Metal, VM, and Exadata.
  2. Choose your Compartment.
  3. In the list of DB systems, find the Exadata DB system for which you want to enable IORM, and click its highlighted name.

    The system details are displayed, showing the IORM status as "Disabled."

  4. Cick Enable IORM.

    It might take a minute for the Enable I/O Resource Management dialog to retrieve the DB system information.

  5. Select the objective to apply to the resource plan:

    • Auto - (Recommended) Dynamically changes the objective based on the resource plan and observed workloads.
    • Balanced - Weighs high throughput and low latency evenly.
    • High throughput - Provides the best throughput for DSS workloads.
    • Low latency - Provides the best latency for critical OLTP workloads.
  6. Configure the resource plan default directive by setting the number of shares. This number of shares is assigned to each database not associated with a specific directive.
  7. In the Resource Plan Directives section, add a directive for each database you want to assign a greater or lesser number of shares than the default directive.

    To add a directive, click + Additional Directive, then specify the database and the number of shares for that database.

  8. When you are done adding directives, click Enable.

    While the IORM configuration settings are being applied, the system details page shows the IORM status as "Updating." The update might take several minutes to complete but should have no impact on your ability to perform normal operations on your DB system. After a successful update, the IORM status shows as "Enabled."

To modify the IORM configuration on your Exadata DB system

Use this procedure to change your IORM settings or to disable IORM.

  1. Open the navigation menu. Under Database, click Bare Metal, VM, and Exadata.
  2. Choose your Compartment.
  3. In the list of DB systems, find the Exadata DB system for which you want to modify the IORM configuration, and click its highlighted name.

    The system details are displayed, showing the IORM status as "Enabled."

  4. Click Update IORM.
  5. In the Update I/O Resource Management dialog, take one of the following actions:

    • Change your settings - Specify a new objective and adjust your directives, as applicable, and then click Update.
    • Disable IORM - Click Disable IORM. Disabling IORM removes all your resource plan directives and restores a basic objective for I/O resource management.

    While the new IORM configuration settings are being applied, the system details page shows the IORM status as "Updating." The update might take several minutes to complete but should have no impact on your ability to perform normal operations on your DB system. After a successful update, the IORM status shows as "Enabled" or "Disabled," depending on the action you took.