Today’s XaaS environments claim better service availability and data durability than many IT directors would be comfortable signing up for. These claims need to be understood, but for many of us, that understanding often only comes through the pain of loss. The very well known Amazon Web Services platform, which is, by just about any measure, a model of reliability, makes an interesting statement: “Amazon S3 is designed for 99.99% availability and 99.999999999% durability.” For this discussion, let’s set aside the words “designed for,” that indicate this is an objective not a promise.
Durability and Availability