s3backer is a filesystem that contains a single file backed by the Amazon Simple Storage Service (Amazon S3). As a filesystem, it is very simple: it provides a single normal file having a fixed size. Underneath, the file is divided up into blocks, and the content of each block is stored in a unique Amazon S3 object. In other words, what s3backer provides is really more like an S3-backed virtual hard disk device, rather than a filesystem.
