You're welcome to email me if you like - it's in my profile. Kafka and Samza are intended (generally speaking) to go hand in hand. Samza is a re-imagined datastore that Kafka can shuttle data into. I've been investigating Samza quite heavily specifically for time series data storage. I'd be happy to share thoughts.
While I'm not using Samza, Spark Streaming also works pretty nicely in this case, although it is not so focused on keeping state (it can, though, using the checkpointing system and the `updateStateByKey` transformation) and thus might not perfectly stable if you require to handle failures without reprocessing.
