When Region Servers are co-located with Datanodes, you can utilize short
circuit read feature.
See 12.11.2 of http://hbase.apache.org/book.html#perf.hdfs

Factors to consider co-location include the allocation of memory of server
- so that region server and Data node can have ample memory to fulfill
their tasks.

On Mon, Apr 14, 2014 at 8:59 PM, Shashidhar Rao
NEW: Monitor These Apps!
elasticsearch, apache solr, apache hbase, hadoop, redis, casssandra, amazon cloudwatch, mysql, memcached, apache kafka, apache zookeeper, apache storm, ubuntu, centOS, red hat, debian, puppet labs, java, senseiDB