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Add information on tuning kern.maxvnodes.

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PR:		docs/80267
Submitted by:	Brad Davis <so14k@so14k.com>
Approved by:	trhodes (mentor)
This commit is contained in:
Jesus R. Camou 2005-04-24 03:15:56 +00:00
parent 4dc2e7591e
commit e77d110832
Notes: svn2git 2020-12-08 03:00:23 +00:00 
svn path=/head/; revision=24381
1 changed files with 36 additions and 0 deletions
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en_US.ISO8859-1/books/handbook/config/chapter.sgml
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@ -2229,6 +2229,42 @@ device_probe_and_attach: cbb0 attach returned 12</screen>
</note>
</sect3>
</sect2>
<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 available 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, increasing
<varname>kern.maxvnodes</varname> by a value of 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 visible. More memory should
be active.</para>
</sect3>
</sect2>
</sect1>
<sect1 id="adding-swap-space">