Avoiding unanticipated costs when uploading gateway data

When a file is written to the File Gateway by an NFS client, the File Gateway uploads the file's data to Amazon S3 followed by its metadata. Uploading the file data creates an S3 object, and uploading the metadata for the file updates the metadata for the S3 object. This process creates an additional version of the object. If S3 versioning is turned on, both versions are stored.

If you change the metadata of a file that's stored in your File Gateway, a new S3 object is created and replaces the existing S3 object. This behavior is different from editing a file in a file system, where editing a file does not result in a new file being created. Test all file operations that you plan to use with Amazon Storage Gateway so that you understand how each file operation interacts with Amazon S3 storage.

Carefully consider the use of S3 versioning and Cross-Region replication (CRR) in Amazon S3 when you're uploading data from your File Gateway. Uploading files from your File Gateway to Amazon S3 when S3 versioning is turned on results in at least two versions of an S3 object.

Certain workflows involving large files and file-writing patterns such as file uploads that are performed in several steps can increase the number of stored S3 object versions. If the File Gateway cache needs to free up space due to high file-write rates, multiple S3 object versions might be created. These scenarios increase S3 storage if S3 Versioning is turned on and increase the transfer costs associated with CRR. Test all file operations that you plan to use with Storage Gateway so that you understand how each file operation interacts with Amazon S3 storage.

Using the Rsync utility with your File Gateway results in the creation of temporary files in the cache and the creation of temporary S3 objects in Amazon S3. This situation results in early deletion charges in the S3 Standard-Infrequent Access (S3 Standard-IA) storage class.