<sect2>

      <title>Virtual Memory</title>

      <sect3>

        <title><varname>kern.maxvnodes</varname></title>

        <para>A vnode is the internal representation of a file or

          directory.  So increasing the number of vnodes avaliable to

          the operating system cuts down on disk I/O.  Normally this

          is handled by the operating system and does not need to be

          changed.  In some cases where disk I/O is a bottleneck and

          the system is running out of vnodes, this setting will need

          to be increased.  The amount of inactive and free RAM will

          need to be taken into account.</para>

        <para>To see the current number of vnodes in use:</para>

        <programlisting>&prompt.root; sysctl vfs.numvnodes

vfs.numvnodes: 91349</programlisting>

        <para>To see the maximum vnodes:</para>

        <programlisting>&prompt.root; sysctl kern.maxvnodes

kern.maxvnodes: 100000</programlisting>

        <para>If the current vnode usage is near the maximum, upping

          <varname>kern.maxvnodes</varname> by a 1,000 is probably a

          good idea.  Keep an eye on the number of

          <varname>vfs.numvnodes</varname>.  If it climbs up to the

          maximum again, <varname>kern.maxvnodes</varname> will need to

          be increased further.  A shift in your memory usage as

          reported by &man.top.1; should be visable.  More memory should

          be active.</para>

      </sect3>

    </sect2>