Save money with Jelastic’s new optimised Garbage Collector Agent

Posted on by Dora

garbage_collector_save_moneyA few short months ago we explained how to experiment with custom JVM Garbage Collector settings on our Jelastic PaaS.

The fantastic development team behind Jelastic just announced that they too were hard at work experimenting with the GC, and as a result they’ve introduced new default GC settings to help to provide optimum performance right out of the box for all of your Java applications.

New default Garbage Collector settings

Prior to this update, Jelastic used the Serial GC by default if the Cloudlet Scaling Limit was set at or below 1GB (8 cloudlets), and the G1 GC by default if the Cloudlet Scaling Limit was set above 1GB.

Now, if no custom GC is specified, Jelastic will default to:

  • ParNew for Java servers with resource limits below 8GB

  • G1 for Java servers with resource limits above 8GB (64 cloudlets and higher)

As before, these are just defaults and you can continue to override them with your own settings if desired. Jelastic remains a highly flexible and versatile platform that works with you instead of getting in your way.

A money saving GC agent

Garbage Collection is particularly important on Jelastic due to its unique automatic vertical scaling – releasing unused RAM from the JVM back to the OS means that your hosting charges are reduced.

To help lower your costs, the Jelastic developers have introduced a new GC agent!

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This new GC agent automatically keeps JVM RAM usage more closely matched to application RAM usage. It releases reserved memory and unused RAM, meaning you use fewer cloudlets and save big.

The Jelastic GC agent is automatically enabled for all newly created Java application servers but it only works in combination with the default GC settings. If you change these settings, then the Jelastic GC Agent will be disabled and won’t call Full GC.

You can add the GC agent to existing environments too

You can optionally add the GC agent to your existing Java environments too if you want.

Just upload jelastic-gc-agent.jar to the home folder on your Java server, and follow the instructions outlined in the ‘Enable/Disable’ section of the Jelastic developers’ GC blog post.

Take note that the GC agent only works in conjunction with ParNew or G1 – you may need to set your GC manually for existing environments (since they use Serial or G1 by default).

Customise the GC agent

You can customise the GC agent behaviour to suit your needs (including disabling it completely if desired):

  • the interval of checks can be changed  – by default, the Jelastic GC agent initiates system checks every 15 minutes (beginning from every JVM start);

  • debug mode can be enabled to provide GC logging output;

  • the GC agent can be completely disabled.

These are all described in full in the Jelastic blog post, where you will also find a sample load testing application to illustrate the power of Jelastic’s vertical scaling combined with the new GC agent and how it will save you significant amounts of money!

How much did you save?

We try to make our customers happy every day, so when you test this new feature please share your feedback and help us spread the word about it!

You can always reach our team via our website or tweet us @Layershift – we’re always really pleased to hear from you and eager to help!

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