Any system or service should be accessible when a user wants to perform any action. If a user cannot perform the desired action, it is said to be unavailable or down. So, high availability acts as a very basic requirement for each system or service. In the era of online business, where the internet connects business to millions of customers, a downtime can cause loss of revenue, exacerbate customer relationships, lessen competitive advantages, incur legal obligations, and lower the industry's reputation and investor confidence. An analysis of downtime risk helps businesses to understand the maximum time that an IT-based business process can be down before the organization starts to suffer unacceptable consequences. For a system running a stock exchange, this time in regular business hours is zero, or close to zero.
Another very important...
