High Availability: Design, Techniques, and Processes

Chapter 2. Achieving Higher Availability

Determining User Availability Requirements

The first step in designing for availability is to discover your users' true requirements for availability — and for IT services in general. This requires close consultation with as many users as possible, covering at least users of critical applications. The initial response of most users is that the system must be available all the time. Of course, you need to explain that the cost for providing system availability gets higher and higher as more availability is needed. You'll also need to explain that these costs will be passed on to them somehow — either directly, as IT chargeback for services, or (as in most small-to-mid-sized companies) indirectly, as ...