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<appref>
<header>
<copyright>
<year>1996</year><year>2009</year>
<holder>Ericsson AB. All Rights Reserved.</holder>
</copyright>
<legalnotice>
The contents of this file are subject to the Erlang Public License,
Version 1.1, (the "License"); you may not use this file except in
compliance with the License. You should have received a copy of the
Erlang Public License along with this software. If not, it can be
retrieved online at http://www.erlang.org/.
Software distributed under the License is distributed on an "AS IS"
basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
the License for the specific language governing rights and limitations
under the License.
</legalnotice>
<title>os_mon</title>
<prepared></prepared>
<docno></docno>
<date></date>
<rev></rev>
</header>
<app>os_mon</app>
<appsummary>OS Monitoring Application</appsummary>
<description>
<p>The operating system monitor, OS_Mon, provides the following
services:</p>
<list type="bulleted">
<item><seealso marker="cpu_sup">cpu_sup</seealso>
CPU load and utilization supervision (Unix)</item>
<item><seealso marker="disksup">disksup</seealso>
Disk supervision(Unix, Windows)</item>
<item><seealso marker="memsup">memsup</seealso>
Memory supervision (Unix, Windows, VxWorks)</item>
<item><seealso marker="os_sup">os_sup</seealso>
Interface to OS system messages (Solaris, Windows)</item>
</list>
<p>To simplify usage of OS_Mon on distributed Erlang systems, it is
not considered an error trying to use a service at a node where it
is not available (either because OS_Mon is not running, or because
the service is not available for that OS, or because the service
is not started). Instead, a warning message is issued via
<c>error_logger</c> and a dummy value is returned, which one is
specified in the man pages for the respective services.</p>
</description>
<section>
<title>Configuration</title>
<p>When OS_Mon is started, by default all services available for
the OS, except <c>os_sup</c>, are automatically started. This
configuration can be changed using the following application
configuration parameters:</p>
<taglist>
<tag><c>start_cpu_sup = bool()</c></tag>
<item>
<p>Specifies if <c>cpu_sup</c> should be started. Defaults to
<c>true</c>.</p>
</item>
<tag><c>start_disksup = bool()</c></tag>
<item>
<p>Specifies if <c>disksup</c> should be started. Defaults to
<c>true</c>.</p>
</item>
<tag><c>start_memsup = bool()</c></tag>
<item>
<p>Specifies if <c>memsup</c> should be started. Defaults to
<c>true</c>.</p>
</item>
<tag><c>start_os_sup = bool()</c></tag>
<item>
<p>Specifies if <c>os_sup</c> should be started. Defaults to
<c>false</c>.</p>
</item>
</taglist>
<p>Configuration parameters effecting the different OS_Mon services
are described in the respective man pages.</p>
<p>See <seealso marker="kernel:config">config(4)</seealso> for
information about how to change the value of configuration
parameters.</p>
</section>
<section>
<title>SNMP MIBs</title>
<p>The following MIBs are defined in OS_Mon:</p>
<taglist>
<tag>OTP-OS-MON-MIB</tag>
<item>
<p>This MIB contains objects for instrumentation of disk,
memory and CPU usage of the nodes in the system.</p>
</item>
</taglist>
<p>The MIB is stored in the <c>mibs</c> directory. It is defined
in SNMPv2 SMI syntax. An SNMPv1 version of the MIB is delivered
in the <c>mibs/v1</c> directory.</p>
<p>The compiled MIB is located under <c>priv/mibs</c>, and
the generated <c>.hrl</c> file under the <c>include</c> directory.
To compile a MIB that IMPORTS the <c>OTP-OS-MON-MIB</c>, give
the option <c>{il, ["os_mon/priv/mibs"]}</c> to the MIB compiler.</p>
<p>If the MIB should be used in a system, it should be loaded into
an agent with a call to <c>os_mon_mib:load(Agent)</c>, where
<c>Agent</c> is the pid or registered name of an SNMP agent. Use
<c>os_mon_mib:unload(Agent)</c> to unload the MIB.
The implementation of this MIB uses Mnesia to store a cache with
data needed, which implicates that Mnesia must be up and running.
The MIB also use functions defined for the <c>OTP-MIB</c>, thus
that MIB must be loaded as well.</p>
</section>
<section>
<title>See Also</title>
<p><seealso marker="cpu_sup">cpu_sup(3)</seealso>,
<seealso marker="disksup">disksup(3)</seealso>,
<seealso marker="memsup">memsup(3)</seealso>,
<seealso marker="os_sup">os_sup(3)</seealso>,
<seealso marker="nteventlog">nteventlog(3)</seealso>,
<seealso marker="snmp:snmp">snmp(3)</seealso>.</p>
</section>
</appref>
