Before choosing a cloud vendor, do your due diligence by examining the SLA to understand what it guarantees and what it doesn’t, and scour through any publicly accessible availability data. Amazon, for example, maintains a “Service Health Dashboard” that shows current and historical uptime status of its various services.
There will always be some network latency with a cloud service, possibly making it slower than an application that runs in your local data center. But a new crop of third-party vendors are building services on top of the cloud to make sure applications can scale and perform well, such as RightScale.
By and large, the performance hit related to latency “is pretty negligible these days,” RightScale CTO Thorsten von Eicken. The largest enterprises are distributed throughout the country or world, he notes, so many users will experience a latency-caused performance hit whether an application is running in the cloud or in the corporate data center.