Whether you want CloudFront to automatically compress content for web requests that include Accept-Encoding: gzip in the request header. If so, specify true; if not, specify false. CloudFront compresses files larger than 1000 bytes and less than 1 megabyte for both Amazon S3 and custom origins. When a CloudFront edge location is unusually busy, some files might not be compressed. The value of the Content-Type header must be on the list of file types that CloudFront will compress. For the current list, see Serving Compressed Content (http://docs.aws.amazon.com/console/cloudfront/compressed-content) in the Amazon CloudFront Developer Guide. If you configure CloudFront to compress content, CloudFront removes the ETag response header from the objects that it compresses. The ETag header indicates that the version in a CloudFront edge cache is identical to the version on the origin server, but after compression the two versions are no longer identical. As a result, for compressed objects, CloudFront can't use the ETag header to determine whether an expired object in the CloudFront edge cache is still the latest version.