Igniters, MultiMap should be really great addition to the Ignite fabric, as it provides an easy-to-use API to work with time-series data.
I have added a detailed design description to the IgniteMultiMap ticket: https://issues.apache.org/jira/browse/IGNITE-640 Vladislav Jelisavcic, the ticket is currently assigned to you. If you still intend to work on it, please review it and let us know if the design makes sense. Also, would be nice if others could review it and provide comments as well. D.