"Tracking events is an important problem for ad tech companies which rely on notifications fired at the time of ad rendering as a feedback loop to the machine learning algorithms and to adjust several key real time metrics. This talk showcases the EventTracker, which is a large scale, Redis powered storage service for handling event notifications built at Rocket Fuel. We discuss how we initially used Redis RC-1 to build EventTracker and our migration to the stable release. We showcase our smart client-side failover mechanisms for when the Redis nodes are not reachable. We shed light on the problems we have faced when scaling this service and the manner in which we have dealt with each of these problems."