question Re: Using G1GC of JDK 8 on Cloudera in Support Questions

Using G1GC of JDK 8 on Cloudera

hores — Fri, 16 Sep 2022 14:11:32 GMT

Hi,

We have CDH 5.15 on our production cluster with JDK 8,

What is your recommendation about moving to G1GC or stay with the CMS,

didn't find any clear instruction about it.

Does it depend on the CDH version? or on the components I'm using?

Thanks

Re: Using G1GC of JDK 8 on Cloudera

Consult — Tue, 05 Mar 2019 10:35:26 GMT

Hello @hores,

If you plan to use and enable G1 GC for all your YARN jobs then please modify YARN's Configuration -> "Map Task Java Opts Base" and "Reduce Task Java Opts Base".

Hope that helps.

Re: Using G1GC of JDK 8 on Cloudera

hores — Tue, 05 Mar 2019 10:51:06 GMT

Hi @Consult,

1. What is your recommendation about it? It is better to use it on all your components (Hive, ImpalaEmbeddedJVM, YARN, hdfs etc) or not? are their some exceptional components?

2. How do I configure theImpalaEmbeddedJVM ?

Thanks

Re: Using G1GC of JDK 8 on Cloudera

Consult — Wed, 06 Mar 2019 09:28:33 GMT

Hello @hores,

I am not sure about your use case scenario to opt for g1. But as per most of the GC test, cms still seems to the best and default option. G1 may have improved latency but throughput is still a challenge in many tested scenario.

Also, you may review tunning GC for HBase.

Hope that helps.