Scaling out on the Cloud is all the rage. One of the mystiques of the Cloud is the ability to handle increased demand on short notice. However, scaling out is not for everyone. Many companies have to perform substantial re-writes to their application in order to use software that lets you add servers on the fly. These programs operate based on rule sets that are triggered by monitoring software. Database servers are a common trouble point for scaling out, because modifying your application to handle multiple database servers almost always requires changes to applications.
Application re-writes necessary to realize the benefits of products that offer automatic scaling out can be very expensive both in terms of time and money. This represents a significant barrier to entry for many businesses running mission-critical applications because they need to be sure the scaling will occur in a way that enhances, not decreases the user experience.
