jvm-args.md

JVM Args

The following JVM Args are supported when starting the embedded server.

heapSize

You can set the max heap size the server is allowed to have (-Xmx) by passing the heapSize parameter to the start command. This parameter defaults to megabytes but you can specify any valid suffix.

start heapSize=1024

In server.json

server set JVM.heapSize=1024
server set JVM.heapSize=2G
server show JVM.heapSize

minHeapSize

You can set the starting heap size for the server (-Xms) by passing the minHeapSize parameter to the start command. This parameter defaults to megabytes but you can specify any valid suffix.

start minHeapSize=1024

In server.json

server set JVM.minHeapSize=1024
server set JVM.minHeapSize=2G
server show JVM.minHeapSize

Ad Hoc JVM Args

You can specify ad-hoc JVM args for the server with the JVMArgs parameter.

start JVMArgs="-XX:MaxGCPauseMillis\=200"

In server.json

server set JVM.args="-XX:MaxGCPauseMillis\=200"
server show JVM.args

JVM args can also be set an array of strings which prevents you from needing to escape or quote anything.

{
  "jvm" : {
    "args" : [
       "-XX:+UseG1GC",
       "-XX:-CreateMinidumpOnCrash",
       "--add-opens=java.base/java.net=ALL-UNNAMED"
    ]
  }
}

Or via the CLI like so:

server set jvm.args=["-XX:+UseG1GC"]
server set jvm.args=["-XX:-CreateMinidumpOnCrash"] --append
server set jvm.args=["--add-opens=java.base/java.net=ALL-UNNAMED"] --append

Ad Hoc Runwar Options

You can specify ad-hoc options for the underlying Runwar library using the RunwarArgs parameter.

start RunwarArgs="--sendfile-enable false"

In server.json

server set runwar.args="--sendfile-enable false"
server show runwar.args

Runwar args can also be set an array of strings which prevents you from needing to escape or quote anything.

{
  "runwar" : {
    "args" : [
      "--runwar-option",
      "value",
      "--runwar-option2",
      "value2"
    ]
  }
}

Or via the CLI like so:

server set runwar.args=["--runwar-option","value"]
server set runwar.args=["--runwar-option2","value2"] --append