eG Monitoring
 

Measures reported by AWSEc2DCStatusTest

Amazon has data centers in different areas of the world (e.g., North America, Europe, Asia, etc.). Correspondingly, EC2 is available to use in different Regions. Each Region contains multiple distinct locations called Availability Zones (illustrated in the following diagram). Each Availability Zone is engineered to be isolated from failures in other Availability zones and to provide inexpensive, low-latency network connectivity to other zones in the same Region. By launching instances in separate Availability Zones, you can protect your applications from the failure of a single location.

If users complaint that their server instances are inaccessible, you may want to know whether it is because of the non-availability of the availability zone within which the instances have been launched. This test auto-discovers the availability zones configured within the monitored EC2 region, and reports the availability of each zone.

The measures made by this test are as follows:

Measurement Description Measurement Unit Interpretation
Availability Indicates whether/not this availability zone is currently available. Number The value 0 indicates that the availability zone is Not Available and the value 100 indicates that it is Available.

If an availability zone fails, then all server instances operating within that zone will also be rendered unavailable. If you host all your Amazon EC2 instances in a single location that is affected by such a failure, your instances will be unavailable, thereby bringing your entire application to a halt.

On the other hand, if you have instances distributed across many Availability Zones and one of the instances fails, you can design your application so the instances in the remaining Availability Zones handle any requests.