We've introduced a new feature called Instant Alerts. Its an optional service which you can use to get notified when there is a problem with your site. You can specify a list of email addresses and/or mobile numbers to receive the alerts at.
At the moment you can receive alerts when your origin server:
- Times out
- Cannot be reached at all
- Returns an error
Just so you don't get bombarded with messages there is a cool down limit ranging from 30 minutes to 24 hours which you can choose per alert.
If you're using a service like pingdom to check that your site is up you probably will want to enable Instant Alerts. Services like Pingdom might be getting pages served by our cache while your origin server is actually down.