Tune HDFS garbage collection
-XX:+UseCMSInitiatingOccupancyOnly
prevents the use of GC heuristics.
- -XX:CMSInitiatingOccupancyFraction=<percent>
tells the Java VM when the CMS collector should be triggered.
If this percent is set too low, the CMS collector runs too often; if it is set too
high, the CMS collector is triggered too late, and concurrent mode failure might occur. The
default setting for -XX:CMSInitiatingOccupancyFraction
is 70, which
means that the application should utilize less than 70% of capacity. To tune garbage
collection by modifying the NameNode CMS GC parameters, follow these
steps:
- In Ambari Web, browse to .
- Open the Configs tab and browse to .
- Edit the hadoop-env template.
- Save your configurations and restart, as prompted.