Good reference articles on Hadoop based solution architectures

http://hortonworks.com/blog/modern-financial-services-architectures-built-hadoop/

How to run a simple mapreduce job to verify the cluster health?

Many times you want to check if cluster is in good shape... run this command that does not require much setup...

$ hadoop jar /usr/lib/gphd/hadoop-mapreduce/hadoop-mapreduce-examples-*.jar pi 10 1000