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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>