The CloudStatus service reports Simple Storage Service health based on the availability of S3 to process PUT and GET operations from inside and outside the cloud, and the throughout for PUT and GET operations on EC2 instances of each size.
Throughput is reported by issuing S3 requests from US-based EC2 instances to S3 buckets in the US and Europe. "Moderate I/O" metrics reflect throughput for operations on Small EC2 instances. "High I/O" metrics reflect throughput for operations on Large and Extra Large EC2 instances.
The health of an AWS service is an indicator of its current and recent quality of service. Health reflects the availability of a service and the performance of key service operations, invoked from both inside and outside the cloud. Service health is indicated on charts as:
Healthy—indicates full health and satisfactory performance
Issues—indicates partial health, instances of less than satisfactory performance, or both
Service Failure—indicates service not available, or poor health