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<p class="MsoNormal" style="margin-left:36.0pt"><b><span style="font-family:Calibri;color:black">From:
</span></b><span style="font-family:Calibri;color:black">Yujun Zhang <zhangyujun+zte@gmail.com><br>
<b>Date: </b>Thursday, 12 January 2017 at 17:37<br>
<br>
</span><o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">On Thu, Jan 12, 2017 at 5:12 PM Afek, Ifat (Nokia - IL) <<a href="mailto:ifat.afek@nokia.com">ifat.afek@nokia.com</a>> wrote:<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"> <o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">'deduced' vs 'monitored' would be good enough for most cases. Unless we have identify some real use case, I also think there is no need for bring in quantitative indicator like counter or probability.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">[Ifat] I agree.<o:p></o:p></p>
<p class="MsoNormal"> <o:p></o:p></p>
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Personally, I don’t think this is needed. I think that if Nagios reports an error, then it is confident enough without getting it from another monitor.<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">You are right. We would consider a reported alarm as a reliable indicator of fault. What I was thinking about is: when we the alarm is not seen, can we be sure there is no fault? <o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">Another situation is slow upstream alarm with fast downstream alarm. I don't have an actual example for the moment, so please allow me to imagine an extreme condition.<o:p></o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">Suppose host fault will cause instance fault. But due to some restriction, the host fault is scanned every 1 hour, but instance fault can be scanned every 1 second. Now, we get alarms from 10 instance in the same
host. Can we deduce that the host is likely in fault status? And we may raise a "deduced" alarm on the host and trigger an immediate scan which may result in a "monitored" alarm. In this way, we reduce the time of detecting the root cause, i.e host fault.<o:p></o:p></p>
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<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">[Ifat] I understand the use case.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal" style="margin-left:36.0pt"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-left:36.0pt">An alternative solution is to distinguish fault from alarm. Alarm is actually a reflection of fault status. Beside the directly linked alarm, fault status can also be deduced from downstream alarms. I haven't
think over this model yet, it just flashed over my mind. Any comments are welcome.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">[Ifat] Isn’t ‘fault vs. alarm’ just a different terminology for ‘deduced vs. monitored’?<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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