At Foursquare, work was being done to put Hypertable under Graphite. It was incredible to use (my year+ queries returned in tens of milliseconds), but I don't know what came of it. Hypertable is criminally overlooked in the industry, and TSDB is a killer app; a little bit of glue code and you've basically invented a crude clone of Google's monitoring, with that stack.

I've looked at Cyanite, and it has the same accuracy problem as Graphite, which I describe in my blog post. Also I'm leaning towards the conclusion that something like Cassandra, which was design for Facebook scale is even a suitable store for something as compact as TS, which is just a stream of floats.