Cloud Harmony has posted reliability ratings for thirty different cloud computing providers. Among the largest providers, Amazon’s EC2 appeared to have the best ratings for a compute service, achieving 99.9974 percent uptime. By comparison, Rackspace Cloud Servers had 99.9889 percent, Google Compute Engine achieved 99.9816 percent, and Microsoft Azure Virtual Machines reached 99.9359 percent uptime.
The Cloud Harmony service also tracks storage, CDN, DNS and PaaS services. In addition, it provides real-time information about the current status of cloud services.