Date: Fri, 22 Apr 2005 16:33:01 -0600 (MDT) From: Brad Davis <so14k@so14k.com> To: FreeBSD-gnats-submit@FreeBSD.org Subject: docs/80267: Add information on tuning kern.maxvnodes Message-ID: <20050422223301.E13D9B86C@mccaffrey.house.so14k.com> Resent-Message-ID: <200504222240.j3MMeGml087564@freefall.freebsd.org>
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>Number: 80267 >Category: docs >Synopsis: Add information on tuning kern.maxvnodes >Confidential: no >Severity: non-critical >Priority: low >Responsible: freebsd-doc >State: open >Quarter: >Keywords: >Date-Required: >Class: update >Submitter-Id: current-users >Arrival-Date: Fri Apr 22 22:40:16 GMT 2005 >Closed-Date: >Last-Modified: >Originator: Brad Davis >Release: FreeBSD 5.4-STABLE i386 >Organization: >Environment: System: FreeBSD mccaffrey.house.so14k.com 5.4-STABLE FreeBSD 5.4-STABLE #0: Wed Apr 20 22:22:19 MDT 2005 root@mccaffrey.house.so14k.com:/usr/obj/usr/src/sys/SMP i386 >Description: Add information on tuning kern.maxvnodes. >How-To-Repeat: >Fix: --- doc-ori/en_US.ISO8859-1/books/handbook/config/chapter.sgml Fri Apr 22 11:51:50 2005 +++ doc/en_US.ISO8859-1/books/handbook/config/chapter.sgml Fri Apr 22 15:58:09 2005 @@ -2228,6 +2228,42 @@ </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 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> </sect1> <sect1 id="adding-swap-space"> >Release-Note: >Audit-Trail: >Unformatted:
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