SYMPTOM: We have some alerts about high heap size in datanode in Ambari for production cluster. The maximum of heap size of the datanode is set to 16G
ERROR: Below is the snapshot
ROOT CAUSE: DN operations are IO expensive do not require 16GB of the heap.
RESOLUTION: Tuning GC parameters resolved the issue -
4GB Heap recommendation :
-Xms4096m -Xmx4096m -XX:NewSize=800m
I have this issue in my HDP 2.4.2 cluster since midnight because I see some are high on Datanode heap size for more than 10 hours now. I see your resolution but can you be more specific where to change these parameters? should i change them in hadoop-env.sh? and how?
@PJ If you are using ambari, then you need to modify Services->HDFS->Configs->"hadoop-env template" [depending on your java version you are using ie. >Java 8 or <Java 8]
I will just try that