Software Testing Against High Availability

High availability is the ability to provide a service to an end-user with as little perceived downtime as possible. If a system component fails for any reason , the high availability solution ensures that another component takes over for the failed component, and that the newly composed system will maintain the same machine identifications (host names and IP addresses) as the system prior to failure, minimizing the disruption to the user.High availability does not mean that a service is guaranteed to always be available. Analysts describe a range of high availability targets, from the so-called″five nines″availability, with 99.999% up-time, at the high end, to basic availability at 95%. Five nines availability translates to five minutes or less downtime in a full year of 24 by 7 operations. By contrast, 99% availability allows up to 87 hours of downtime per year, and 95% allows up to 436 hours, or 18 days,of downtime, with the cost of providing high availability increases exponentially as the target moves from 95% to 99% to 99.999%. In the context of P8 Products which will based on Server Farm to build the Web Service High Availability system and on Server Cluster to build the back end Service and DataBase High Availability system.Due to the complexity of a High Availability System,it's hard for a software provider to test its products fully,so a test method against High Availability System is needed,and this kind of test method includes three major steps:manual test,automation and high availability test,the iteration of them is the key to guarantee of a high availability system.