The volume gateway represents the family of gateways that support block-based volumes,
previously referred to as gateway-cached and gateway-stored modes
Stored Volume mode – the entire dataset is stored on-site and is
asynchronously backed up to S3 (EBS point-in-time snapshots). Snapshots are incremental and
compressed
Cached Volume mode – the entire dataset is stored on S3 and a cache of the
most frequently accessed data is cached on-site
A file gateway is not a mode but a different type of AWS Storage Gateway that provides a
virtual on-premises file server, which enables you to store and retrieve files as objects in
Amazon S3
Virtual Tape Library is not a mode but a gateway that is preconfigured with a media changer
and tape drives