Please see https://issues.apache.org/jira/browse/HADOOP-4801.
Doug Jun Rao wrote:
Hi, Today, HDFS always reads through a socket even when the data is local to the client. This adds a lot of overhead, especially for warm reads. It should be possible for a dfs client to test if a block to be read is local and if so, bypass socket and read through local FS api directly. This should improve random access performance significantly (e.g., for HBase). Has this been considered in HDFS? Thanks, Jun
