Cloud Application Architectures

Amazon S3

Amazon Simple Storage Service (S3) is cloud-based persistent storage. It operates independently from other Amazon services. In fact, applications you write for hosting on your own servers can leverage Amazon S3 without any need to otherwise “be in the cloud.”

When Amazon refers to S3 as “simple storage,” they are referring to the feature set—not its ease of use. Amazon S3 enables you to simply put data in the cloud and pull it back out. You do not need to know anything about how it is stored or where it is actually stored.

You are making a terrible mistake if you think of Amazon S3 as a remote filesystem. Amazon S3 is, in many ways, much more primitive than a filesystem. In fact, you don’t really store “files”—you store objects. Furthermore, you store objects in buckets, not directories. Although these distinctions may appear to be semantic, they include a number of important differences:

• Objects stored in S3 can be no larger than 5 GB.

• Buckets exist in a flat namespace shared among all Amazon S3 users. You cannot create “sub-buckets,” and you must be careful of namespace clashes.

• You can make your buckets and objects available to the general public for viewing.

• Without third-party tools, you cannot “mount” S3 storage. In fact, I am not fond of the use of third-party tools to mount S3, because S3 is so conceptually different from a filesystem that I believe it is bad form to treat it as such.

Access to S3

Before accessing S3, you need to sign up for an Amazon Web Services account. ...