e72bfd15_Cassandra_vs_HBase___WhyNosql__Cassandra
[HBase] Map Reduce support is native. HBase is built on Hadoop. Data does not get transferred. [Cassandra] 
Map Reduce support is new. You will need a hadoop cluster to run it. Data will be tranferred from Cassandra cluster to the hadoop cluster. No suitable for running large data map reduce jobs.
Cassandra vs HBase | WhyNosql
Cassandra