ecearth3/sources/xios-2.5/inputs/Regular_ugrid/iodef.xml

<?xml version="1.0"?>
<simulation>

  <context id="atmosphere" src="./context_atmosphere.xml"/> 

  <context id="xios">
      <variable_definition>
        <variable_group id="buffer">
            <variable id="optimal_buffer_size" type="string">performance</variable>
            <variable id="buffer_size_factor" type="double">1.0</variable>
         </variable_group>

        <variable_group id="parameters" >
          <variable id="info_level" type="int">1</variable>
          <variable id="print_file" type="bool">true</variable>
        </variable_group>
      </variable_definition>
  </context>

</simulation>