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<concept id="GUID-484B27EF-3FA1-5193-97EC-B9699AE49026" xml:lang="en"><title>System
Health Manager Concepts</title><prolog><metadata><keywords/></metadata></prolog><conbody>
<p>This section explains the policies involved in a process monitoring. </p>
<section id="GUID-30C01801-01F4-5C20-9CA0-910498D47982"><title>Relaunch policy</title> <p>Once
a monitored process has failed, SHMA attempts to re-launch the process. If
all re-launch attempts fail, then SHMA either ignores the failure of the process,
or restarts the device (for a critical component). </p> <p>If a monitored
component is successfully relaunched, and then subsequently fails, the next
re-launch attempt will only occur after at least <xref href="GUID-38CFBD6A-15CD-343D-8165-836AB53B29E2.dita"><apiname>KWaitTime</apiname></xref> seconds
has elapsed (since the last re-launch attempt). This mechanism is referred
to a ‘re-launch throttling’ </p> <p>SHMA provides a method to control process
restart which involves specifying the ‘rate of failure’ (i.e., restart) of
a monitored process. If the process's failure rate exceeds the value that
is set for the component, no new restart attempts is performed on the component.
The individual restart count decrements (if restart count is greater than
zero) at regular intervals (defined by <xref href="GUID-38CFBD6A-15CD-343D-8165-836AB53B29E2.dita"><apiname>KWaitTime</apiname></xref> patchable
constant). At a restart attempt, if the count exceeds the specified limit,
the process is not restarted and the Retry Failure policy is enacted. </p> </section>
<section id="GUID-6A9855C6-0D0E-5D4F-9042-5BA34F3E002C"><title>Retry failure
policy</title> <p>The purpose of the SHMA is to restart processes which fail
unexpectedly. Retry failure policy specifies the action to be taken by the
System Health Manager if a process fails to restart within the specified limit
(set in the patchable constant <xref href="GUID-38CFBD6A-15CD-343D-8165-836AB53B29E2.dita"><apiname>KWaitTime</apiname></xref>). </p> <p>Following
are the possible courses of action: </p> <ul>
<li id="GUID-0E5D9FC9-198D-54B4-8283-A14C6872D77E"><p>ignore the failure </p> </li>
<li id="GUID-F25405A0-0553-5497-8D89-DB197710B742"><p>restart the OS </p> </li>
<li id="GUID-58F72AFF-8637-5223-8730-FAA9C302FD04"><p>restart the OS in a
different start-up mode (for example, normal mode, textual mode) </p> </li>
</ul> <p>Retry failure policy for each monitoring request must be specified
by the client. The client requires certain capabilities to request each course
of action. </p> <p> <b>NOTE</b>: System Health Manager may be requested to
restart the OS when a critical process fails without attempting to restart
the failed process. </p> </section>
<section><title>Capabilities required </title> <p>When requesting monitoring,
a client requires the following capabilities: </p> <table id="GUID-38587108-0309-5868-9CCC-3C8ABD536E5C">
<tgroup cols="3"><colspec colname="col0"/><colspec colname="col1"/><colspec colname="col2"/>
<thead>
<row>
<entry>Retry Failure Policy</entry>
<entry>Description</entry>
<entry>Capability Required</entry>
</row>
</thead>
<tbody>
<row>
<entry><p> <codeph>ESsmIgnoreOnFailure</codeph>  </p> </entry>
<entry><p>Failure to restart is ignored, no action is taken. </p> </entry>
<entry><p>None (for self monitoring) </p> <p> <codeph>ProtServ</codeph> (for
monitoring another process) </p> </entry>
</row>
<row>
<entry><p> <codeph>ESsmRestartOS</codeph>  </p> </entry>
<entry><p>System is restarted in normal mode. </p> </entry>
<entry><p> <codeph>ProtServ</codeph>  </p> </entry>
</row>
<row>
<entry><p> <codeph>ESsmRestartOSWithMode</codeph>  </p> </entry>
<entry><p>System is restarted in a specific start-up mode based on a value
set in the ROM. </p> </entry>
<entry><p> <codeph>ProtServ</codeph> and <codeph>PowerMgmt</codeph>  </p> </entry>
</row>
<row>
<entry><p> <codeph>ESsmCriticalNoRetries</codeph>  </p> </entry>
<entry><p>System is restarted (with no attempts to restart the component being
attempted). </p> </entry>
<entry><p> <codeph>ProtServ</codeph>  </p> </entry>
</row>
</tbody>
</tgroup>
</table> </section>
<section><title>See also</title> <ul>
<li><p><xref href="GUID-8BC13552-7C7D-52AC-AF91-1BB7476912AF.dita">System Health
Manager Overview</xref></p></li>
<li><p><xref href="GUID-723F8716-1FDD-57B4-B685-672D3A755592.dita">Requesting and
canceling monitoring for a process</xref></p></li>
</ul></section>
</conbody></concept>