How can I troubleshoot 503 Slow Down errors when I transfer data between Amazon S3 buckets in different AWS Regions?

Last updated: 2020-01-15

I'm trying to perform a copy operation between two Amazon Simple Storage Service (Amazon S3) buckets in different AWS Regions. However, Amazon S3 returns a response similar to the following:

"AmazonS3Exception: Slow Down (Service: Amazon S3; Status Code: 503; Error Code: 503 Slow Down; Request ID: A4DBBEXAMPLE2C4D)"

How can I troubleshoot this error?


You can send 3,500 PUT/COPY/POST/DELETE or 5,500 GET/HEAD requests per second per prefix in an S3 bucket. When Amazon S3 returns a 503 Slow Down response, this typically indicates that the requests exceed those request rates per prefix. In some cases though, Amazon S3 can return a Slow Down response if your requests exceed the amount of bandwidth available for cross-Region copying.

To troubleshoot the Slow Down error, consider the following approaches:

For other ways to copy data between Regions, consider the following options:

  • Try a GET operation from the source bucket, and then a PUT operation to the destination bucket.
  • Enable cross-Region replication (CRR) on the source bucket. CRR automatically and asynchronously copies objects to the destination bucket.
    Note: After you enable CRR, new objects are automatically copied to the destination bucket. Objects that were in the source bucket before enabling CRR are not automatically copied.

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