The concepts of high availability and fault tolerance are rapidly gaining importance among companies which accept credit card payments. The concepts are especially relevant for enterprise merchants who process transaction around the world 24/7. Payment systems of such large-size merchants must always be available. On the other hand, payment gateway software and other applications have to be regularly updated, which requires some maintenance time. In this situation high availability solutions are the only option.
High availability solutions allow companies to solve several kinds of problems. They reduce system downtime to minimum. They prevent physical hardware failures, and even if such failures occur, the customers may not even notice them (fault tolerance is no less important than high availability). They allow payment software providers to optimize resource usage and organize efforts in the best way in terms of division of labor.
That is why in the context of customer service and credit card payment processing the concepts of high availability and fault tolerance are crucial. You are welcome to find more information on fault tolerance and high availability in the respective article on Paylosohy.com website.