Gruffalo is an asynchronous Netty based graphite proxy. It protects Graphite from the herds of clients by minimizing context switches and interrupts; by batching and aggregating metrics.
Gruffalo also allows you to replicate metrics between Graphite installations for DR scenarios, for example.
Gruffalo can easily handle a massive amount of traffic, and thus increase your metrics delivery system availability.
At Outbrain, we currently handle over 1700 concurrent connections, and over 2M metrics per minute per instance.