Enabling Short Circuit Reads
Because of the partitioned and co-located nature of VectorH, the software is able to utilize HDFS short-circuit reads to good effect. An example for enabling short circuit reads can be found here: HDFS Short-Circuit Local Reads (
http://hadoop.apache.org/docs/r2.7.0/hadoop-project-dist/hadoop-hdfs/ShortCircuitLocalReads.html).
For most distributions this is enabled by default. For instructions on enabling in your environment, consult the Hadoop distribution documentation. Typically, you need to enable libhadoop.so and include property entries in your Hadoop hdfs-site.xml configuration that look similar to this:
<configuration>
<property>
<name>dfs.client.read.shortcircuit</name>
<value>true</value>
</property>
<property>
<name>dfs.domain.socket.path</name>
<value>/var/lib/hadoop-hdfs/dn_socket</value>
</property>
</configuration>
Enabling this feature in Hadoop can improve bulk data loads rates into VectorH by up to 20 percent.