G1GC support on elasticsearch 5.4.3

Question

I am running 5.4.3 version of elasticsearch and currently facing issues with poor performance of CMS. I would like to know if G1GC is supported on 5.4.3 version of elastic-search and if there is any precaution to take while using G1GC.

Answer 1

G1GC is only supported in the last release of elasticsearch (6.5.X). In previous versions, a bootstrap check will prevent your elasticsearch node to start in production mode.

The only way to start with it is to fork the elastic source code and remove the bootstrap check. But elastic.co will refuse to give you support on such a configuration.

More information here and here

Answer 2

Switching garbage collector is not a magic sauce that you sprinkle on your infrastructure to make it work faster. Some things to consider:

1. What is "poor performance"? Throughput, latency, GC times,...? Also what is your bottleneck?
2. The tradeoff between CMS and G1GC are throughput for GC times. While GC times (stop the world) improve in G1GC it can have negative effects on the throughput. That's why it hasn't been recommended for a long time.
3. If you are on JDK8, make sure you are on the latest version. There were some improvements over time.
4. There is a good chance that a newer Elasticsearch version will improve performance more than switching garbage collector.