When you move mission-critical or even moderately critical applications to the cloud, uptime (and performance) is everything.
The cloud seems simple – after all, it acts as one big server and storage array in the sky, right? At a certain level, that is true. But this view obscures real complexity around: choosing the right cloud service, having a proper WAN, and managing and maintaining your cloud connections. At the same time, you need enough bandwidth so your latency-sensitive applications, such as VoIP, perform properly.
A half a decade ago, it seemed cloud services were going down left and right. Amazon Web Services was out for five days; Yahoo Mail had problems as did VMware’s Cloud Foundry development cloud. There are still sporadic issues on the cloud provider side, but at a much lower rate than five years ago. Even so, the largest enterprises find this unacceptable, and with their large budgets can afford a second provider that they can fail over to.