Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Quotas for Amazon Database Migration Service

Following, you can find the resource quotas and naming constraints for Amazon Database Migration Service (Amazon DMS).

The maximum size of a database that Amazon DMS can migrate depends on a number of factors. These include your source environment, the distribution of data in your source database, and how busy your source system is.

The best way to determine whether your particular system is a candidate for Amazon DMS is to test it. Start slowly so you can get the configuration worked out, then add some complex objects. Finally, attempt a full load as a test.

Resource quotas for Amazon Database Migration Service

Each Amazon account has quotas for each Amazon Region on the number of Amazon DMS resources that can be created. After a quota for a resource has been reached, additional calls to create that resource fail with an exception.

The following table lists the Amazon DMS resources and their quotas for each Amazon Region.

For more information on the API request throttling quota and refresh rate, see Understanding API request throttling.

The 30,000-GB quota for storage applies to all your Amazon DMS replication instances in a given Amazon Region. This storage is used to cache changes if a target can't keep up with a source, and for storing log information.

Understanding API request throttling

Amazon DMS supports a varying, but maximum API request quota of 200 API calls per second. In other words, your API requests are throttled when they exceed this rate. Also, you can be limited to fewer API calls per second, depending on how long it takes Amazon DMS to refresh your quota before you make another API request. This quota applies both when you make API calls directly and when they are made on your behalf as part of using the Amazon DMS Management Console.

To understand how API request throttling works, it helps to imagine that Amazon DMS maintains a token bucket that tracks your API requests. In this scenario, each token in the bucket allows you to make a single API call. You can have no more than 200 tokens in the bucket at any one time. When you make an API call, Amazon DMS removes one token from the bucket. If you make 200 API calls in under a second, your bucket is empty and any attempt to make another API call fails. For each second that you don't make an API call, Amazon DMS adds 8 tokens to the bucket, up to the 200 token maximum. This is the Amazon DMS API request refresh rate. At any point after throttling, when you have tokens added to your bucket, you can make as many additional API calls as tokens available until your calls are throttled again.

If you are using the Amazon CLI to run API calls that are throttled, Amazon DMS returns an error like the following:

An error occurred (ThrottlingException) when calling the AwsDmsApiCall operation (reached max retries: 2): Rate exceeded

Here, AwsDmsApiCall is the name of the Amazon DMS API operation that was throttled, for example, DescribeTableStatistics. You can then retry or make a different call after sufficient delay to avoid throttling.