Google recently announced System Status and Quota details Dashboards
The new System Status Site provides a detailed view into the performance of various App Engine components using some of the same raw monitoring data that our engineering team uses internally. This includes:
* up-to-the-minute overview of our system status with real-time, unedited data
* daily overall serving status for each of our APIs, including any outages or downtime
* detailed historical latency and error-rate graphs for the App Engine Datastore, Images, Mail, Memcache, Serving, URL Fetch, and Users components
This makes it easier to track how much of the free quota your app is using up across bandwidth, CPU, etc. Use it to get detailed information about all of the resource quotas that affect your application.