Date Added: Oct 2009
Enterprise applications must continue running, even in the event of an unforeseen/unplanned outage. Outages can be caused by a number of events - hardware or software failures, network outages, power outages, or natural disasters. No matter the cause of the outage, enterprise applications need to be restarted on alternate resources, addressing unplanned downtime. However, there are many approaches to ensuring high availability, ranging from deployment of highly reliable hardware to the presence of high availability software that ensures that applications can run on alternate resources and, if needed, on fault-tolerant systems that have fully redundant hardware coupled with lockstep software. Most systems fit somewhere along this high-availability spectrum in terms of the way that they are protected from downtime.