Tuning your server for OpenJ9

(The canonical version of this post is on the Paper forums. I have cross-posted this as a resource for others.)

Recently, there’s been quite a few people interested in using OpenJ9 to run their server.

If you are not aware of what OpenJ9, it’s a replacement for the standard HotSpot JVM you would get if you installed Java. There are reasons why you may want to switch, including:

  • Ahead-of-Time compilation for fast startup without losing the benefits of a optimizing JIT
  • Specifically tuned for cloud setups (however, it will run fine on bare metal)
  • Reduced memory usage (get a lot more people on your server)
  • Idle garbage collection when your server is not active
  • Much more…

I have compiled a full guide and posted it on my blog. Several people are already using these flags with success. I have even included a shell script that automatically tunes the server for you.

Please let me know about your experience!

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I’ve just switched to this! And so far it looks great. Will look out for the memory usage etc :wink: