Live instructor-led & Self-paced Online Certification Training Courses (Big Data, Hadoop, Spark) › Forums › Hadoop › How to configure hadoop to reuse JVM for mappers? This topic contains 1 reply, has 1 voice, and was last updated by dfbdteam3 1 year, 6 months ago. Viewing 2 posts - 1 through 2 (of 2 total) Author Posts September 20, 2018 at 11:22 am #4618 dfbdteam3Moderator Every time a new Map/Reduce task is started, a new JVM is launched. As we know JVM launch is a costly process, how to configure hadoop to re-use the jvm of old mapper/reducer. September 20, 2018 at 11:22 am #4619 dfbdteam3Moderator To configure Hadoop to reuse JVM for mappers, we just need to add entry in the configuration file: $HADOOP_HOME/conf/mapred-site.xml <property> <name>mapred.job.reuse.jvm.num.tasks</name> <value>-1</value> </property> We need to specify a number value how many times the JVM is to be reused (default is 1), or one can set to -1 for no limit on the reuse of JVM. Author Posts Viewing 2 posts - 1 through 2 (of 2 total) You must be logged in to reply to this topic.