Hardware and Scaling

How do I determine which initial DB Instance class and storage capacity are appropriate for my needs?

In order to select your initial DB Instance class and storage capacity, you will want to assess your application’s compute, memory and storage needs. For more guidelines on picking the right DB Instance class and storage capacity, please refer to Sizing Your Amazon RDS DB Instance in the Amazon RDS User Guide.

How do I scale the compute resources and/or storage capacity associated with my Amazon RDS Database Instance?

You can scale the compute resources and storage capacity allocated to your DB Instance with the ModifyDBInstance action or the AWS Management Console (selecting the desired DB Instance and clicking the Modify button). Memory and CPU resources are modified by changing your DB Instance class, and storage available is changed when you modify your storage allocation. When you modify your DB Instance class or allocated storage, your requested changes will be applied during your specified maintenance window. Alternatively, you can use the apply-immediately flag to apply your scaling requests immediately. Bear in mind that any other pending system changes will also be applied.

You can monitor the compute and storage resource utilization of your DB Instance, for no additional charge, by using Amazon CloudWatch. You can access metrics such as CPU utilization, storage utilization, and network traffic by clicking the Monitoring tab for your DB Instance in the AWS Management Console or by using the Amazon CloudWatch API. To learn more about monitoring your active DB Instances, go to the Amazon RDS Monitoring Guide.

Because of the extensibility limitations of striped storage attached to Windows Server, Amazon RDS does not currently support increasing storage on a SQL Server DB Instance. We recommend that you provision storage according to anticipated future storage growth. If you need to increase the storage of a SQL Server DB Instance, you will need to export the data, create a new DB Instance with increased storage, and then import the data into the new DB Instance. For more information, go to the RDS SQL Server Data Migration Guide.

What is the hardware configuration for Amazon RDS storage?

Amazon RDS uses EBS volumes for database and log storage. Depending on the size of storage requested, Amazon RDS automatically stripes across multiple EBS volumes to enhance IOPS performance. Thus on an existing MySQL or Oracle DB Instance, you may observe some I/O capacity improvement if you scale up your storage. You can scale the storage capacity allocated to your DB Instance using the AWS Management Console or the ModifyDBInstance API.

For SQL Server, because of the extensibility limitations of striped storage attached to Windows Server, Amazon RDS does not currently support increasing storage.

Will my DB Instance remain available during scaling?

The storage capacity allocated to your DB Instance can be increased while maintaining DB Instance availability. However, when you decide to scale the compute resources available to your DB Instance up or down, your database will be temporarily unavailable while the DB Instance class is modified. This period of unavailability typically lasts only a few minutes, and will occur during the maintenance window for your DB Instance, unless you specify that the modification should be applied immediately.

How can I scale my DB Instance beyond the largest DB Instance class and maximum storage capacity?

Amazon RDS supports a variety of DB Instance classes and storage allocations to meet different application needs. If your application requires more compute resources than the largest DB Instance class or more storage than the maximum allocation, you can implement partitioning, thereby spreading your data across multiple DB Instances.

What are the minimum and maximum limits per DB Instance for Amazon RDS storage?

The maximum storage capacity per DB Instance for all DB engines is 1024 GB, except for SQL Server Express Edition, which limits storage to 10 GB per database, or 300 GB for a single DB instance. The minimum storage capacity for each DB Instance is as follows:

SQL Server Express Edition limits storage to 10 GB per database, which limits the overall usable database storage for SQL Express to 300 GB per DB Instance. Any additional storage that you provision with SQL Server Express may be unusable until you upgrade to a different edition of SQL Server.

You can scale up the storage capacity of a MySQL or Oracle DB Instance by adding at least 10 percent more storage per each increment.