Polyglot Lambda Architecture
OTTO has a number of great postings on the work they are doing. One of the most recent articles is “A tale of two lambdas: The joys of working in a polyglot team.” which speaks volumes to using the right language for the problem you are trying to solve. Spark has really helped to move the lambda concept forwards in the last time period. Would also agree with OTT on Elasticsearch – ELK. Personally not used Graphite, but it does look interesting.
On MLlib, I’ve previously blogged about success with trading research/idea recommendations. Its also worth calling out that Logisitic Regression algorithm is very useful in finding relationship from binary response variables – an example in the trading world is the age old classic RFQ reject/accept.