diff --git a/docs/user-manual/en/perf-tuning.md b/docs/user-manual/en/perf-tuning.md index e05578deae..f131a151a1 100644 --- a/docs/user-manual/en/perf-tuning.md +++ b/docs/user-manual/en/perf-tuning.md @@ -206,6 +206,14 @@ tunings won't apply to JDKs from other providers (e.g. IBM or JRockit) of your queues and the size and number of your messages. Use the JVM arguments `-Xms` and `-Xmx` to set server available RAM. We recommend setting them to the same high value. + + When under periods of high load, it is likely that Artemis will be generating + and destroying lots of objects. This can result in a build up of stale objects. + To reduce the chance of running out of memory and causing a full GC + (which may introduce pauses and unintentional behaviour), it is recommended that the + max heap size (`-Xmx`) for the JVM is set at least to 5 x the `global-max-size` of the broker. + As an example, in a situation where the broker is under high load and running + with a `global-max-size` of 1GB, it is recommended the the max heap size is set to 5GB. - Aggressive options. Different JVMs provide different sets of JVM tuning parameters, for the Sun Hotspot JVM the full list of options