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Amazon Relational Database Service
User Guide (API Version 2014-10-31)

Modifying an Amazon RDS DB Instance and Using the Apply Immediately Parameter

Most modifications to a DB instance can be applied immediately or deferred until the next maintenance window. Some modifications, such as parameter group changes, require that you manually reboot your DB instance for the change to take effect.

Important

Some modifications result in an outage because Amazon RDS must reboot your DB instance for the change to take effect. Review the impact to your database and applications before modifying your DB instance settings.

The Impact of Apply Immediately

When you modify a DB instance, you can applying the changes immediately. To apply changes immediately, you select the Apply Immediately option in the AWS Management Console, you use the --apply-immediately parameter when calling the AWS CLI, or you set the ApplyImmediately parameter to true when using the Amazon RDS API.

If you don't choose to apply changes immediately, the changes are put into the pending modifications queue. During the next maintenance window, any pending changes in the queue are applied.

Important

If you choose to apply changes immediately, any changes in the pending modifications queue are also applied. If any of the pending modifications require downtime, choosing apply immediately can cause unexpected downtime.

Common Settings and Downtime Notes

The following table contains details about which settings you can modify, when the changes can be applied, and whether the changes cause downtime for the DB instance.

Important

If you choose to apply changes immediately, any changes in the pending modifications queue are also applied. If any of the pending modifications require downtime, choosing apply immediately can cause unexpected downtime.

DB Instance Setting When the Change Occurs Downtime Notes

Allocated Storage

If Apply Immediately is set to true, the change occurs immediately.

If Apply Immediately is set to false, the change occurs during the next maintenance window.

No downtime. Performance may be degraded during the change.

Auto Minor Version Upgrade

The change is applied asynchronously, as soon as possible. This setting ignores the Apply Immediately setting.

An outage occurs if a newer minor version is available, and Amazon RDS has enabled automatic patching for that engine version.

Backup Retention Period

If Apply Immediately is set to true, the change occurs immediately.

If Apply Immediately is set to false and you change the setting from a nonzero value to another nonzero value, the change is applied asynchronously, as soon as possible. Otherwise, the change occurs during the next maintenance window.

An outage occurs if you change from 0 to a nonzero value, or from a nonzero value to 0.

Backup Window

The change is applied asynchronously, as soon as possible.

Database Port

The change occurs immediately. This setting ignores the Apply Immediately setting.

The DB instance is rebooted immediately.

DB Instance Class

If Apply Immediately is set to true, the change occurs immediately.

If Apply Immediately is set to false, the change occurs during the next maintenance window.

An outage occurs during this change.

DB Instance Identifier

If Apply Immediately is set to true, the change occurs immediately.

If Apply Immediately is set to false, the change occurs during the next maintenance window.

An outage occurs during this change. The DB instance is rebooted.

DB Parameter Group

The parameter group change occurs immediately. However, parameter changes only occur when you reboot the DB instance manually without failover.

For more information, see Rebooting a DB Instance.

An outage doesn't occur during this change. However, parameter changes only occur when you reboot the DB instance manually without failover.

License Model

If Apply Immediately is set to true, the change occurs immediately.

If Apply Immediately is set to false, the change occurs during the next maintenance window.

An outage occurs during this change.

Maintenance Window

The change occurs immediately. This setting ignores the Apply Immediately setting.

If there are one or more pending actions that cause a outage, and the maintenance window is changed to include the current time, then those pending actions are applied immediately, and an outage occurs.

If you set the window to the current time, there must be at least 30 minutes between the current time and end of the window to ensure any pending changes are applied.

Multi-AZ Deployment

If Apply Immediately is set to true, the change occurs immediately.

If Apply Immediately is set to false, the change occurs during the next maintenance window.

New Master Password

The change is applied asynchronously, as soon as possible. This setting ignores the Apply Immediately setting.

Option Group

If Apply Immediately is set to true, the change occurs immediately.

If Apply Immediately is set to false, the change occurs during the next maintenance window.

If the change results in an option group that enables Oracle OEM, this change can cause a brief (sub-second) period during which new connections are rejected. Existing connections are not interrupted.

Publicly Accessible

The change occurs immediately. This setting ignores the Apply Immediately setting.

Security Group

The change is applied asynchronously, as soon as possible. This setting ignores the Apply Immediately setting.

Storage Type

If Apply Immediately is set to true, the change occurs immediately.

If Apply Immediately is set to false, the change occurs during the next maintenance window.

The following changes all result in a brief outage while the process starts. After that, you can use your database normally while the change takes place.

  • From General Purpose (SSD) to Magnetic.

  • From General Purpose (SSD) to Provisioned IOPS (SSD), if you are using a custom parameter group.

  • From Magnetic to General Purpose (SSD).

  • From Magnetic to Provisioned IOPS (SSD).

  • From Provisioned IOPS (SSD) to Magnetic.

  • From Provisioned IOPS (SSD) to General Purpose (SSD), if you are using a custom parameter group.

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