The availability of a system is determined by the amount of time that it is operational (the system uptime) as compared to the amount of time that service is being denied to one or more users (the system downtime).
Although certain techniques can be used to improve the uptime of an individual system, such as increased operator training and using fault-tolerant components, there comes a point where there is not much more that can be done to add the necessary orders of magnitude to the uptime into the extreme reliability realm we are talking about –it is ultimately determined by hardware and software reliability, operator accuracy, and so on. What active/active technology does is reduce downtime by orders of magnitude.
If a node fails, users at that node can be switched to another operable node. If a database fails, there is another consistent copy in the network that can be used. If a network component fails, alternate routes are provided. Using technology available today, failure recovery can be achieved in seconds or less.
In short, let it fail, but fix it fast.
Active/Active Pages:
- Part 1 - What is an Active/Active System?
- Part 2 - Why Does Active/Active Work?
- Part 3 - Shadowbase Database Synchronization
- Part 4 - Eliminate Planned Downtime
- Part 5 - Why Choose Shadowbase Technology?
