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<topic xml:lang="en-us" id="vboxwatchdog">
  <title><ph conkeyref="vbox-conkeyref-phrases/product-name"/>
    <?oxy_comment_start author="Mhari Duncan" timestamp="20250501T151347+0100" comment="Move to troubleshooting?
Maybe make a section for preventative measures?"?>Watchdog<?oxy_comment_end?></title>
  
  <body>
    <p>The memory ballooning service, formerly known as <userinput>VBoxBalloonCtrl</userinput>, was renamed to
      VBoxWatchdog. This service now incorporates the following host services that are meant to be run in a server
      environment: </p>
    <ul>
      <li>
        <p><b outputclass="bold">Memory ballooning control.</b>
          This service automatically takes care of a VM's configured
          memory balloon. See <xref href="guestadd-balloon.dita">Memory Ballooning</xref>. This
          service is useful for server environments where VMs may
          dynamically require more or less memory during runtime.
        </p>
        <p>The service periodically checks a VM's current memory balloon and its free guest RAM and automatically
          adjusts the current memory balloon by inflating or deflating it accordingly. This handling only applies to
          running VMs having recent Guest Additions installed. </p>
      </li>
      <li>
        <p><b outputclass="bold">Host isolation detection.</b>
          This service provides a way to detect whether the host cannot
          reach the specific <ph conkeyref="vbox-conkeyref-phrases/product-name"/> server instance anymore and
          take appropriate actions, such as shutting down, saving the
          current state or even powering down certain VMs.
        </p>
      </li>
    </ul>
    <p>All configuration values can be either specified using the command line or global extradata, whereas command line
      values always have a higher priority when set. Some of the configuration values also be specified on a per-VM
      basis. So the overall lookup order is: command line, per-VM basis extradata if available, global extradata. </p>
  </body>
</topic>
