> Not a fan of Java-based software either, to be honest.
It makes me sad to see this is still something people say. I hope you reconsider this sentiment and investigate some of the really great Java-based software out there, especially Zookeeper and Kafka.
It's worth checking out how Zookeeper and Kafka did in aphyr's testing:
Every Java-based backed service I have come across, be it ElasticSearch, LogStash, Hadoop or PuppetDB, have all been memory-hogging beasts. Part of this is due to the GC, which tends to use more heap space than the program actually needs. Java is fast, but I have yet to see anyone claim it's lightweight.
Kafka seems to suffer from lack of partition tolerance, by the way, according to Aphyr. Not happy about the fact that it will just wipe a partition upon re-electing a new leader.