How is the APM metric "ping time" measured?
Article ID: 35772
Updated On:
Products
Issue/Introduction
"Ping Time" is a metric on all collectors. What is this actually doing? It is not a true ICMP ping because the customer doesn't allow ICMP traffic and this metric is still working. Can you provide details on what the APM "ping time" metric measures?
Environment
Application Performance Management 10.7 release.
Resolution
APM Documentation (with the link provided below) states the following:
The MOM reports the ping metric for each Collector each time slice. For optimal Workstation responsiveness, be sure that the ping metric is less than 500 ms.
The Introscope ping metric monitors only the lower boundary of the round-trip response time from the MOM to each Collector. This ping time is not the same as the network ping time, which is the sending of an ICMP echo request and getting an echo response.
To view the ping metric, use the Search tab to view metrics named "ping" in the supportability metric section of the Investigator tree. Introscope reports the ping metric for each Collector.
Ping times over the 10-second threshold cause the Enterprise Manager|MOM|Collectors|<[email protected]>:Connected metric to display a value of 2. You can adjust this threshold for your environment by changing the introscope.enterprisemanager.clustering.manager.slowcollectorthreshold property in the IntroscopeEnterpriseManager.properties file.
If the ping time exceeds 60 seconds, the MOM automatically disconnects from the Collector with the slow ping time. The MOM disconnect prevents the entire cluster from hanging.
The metric uses two times in its calculations.
- The first of these is the MOM start time. This is the time that the MOM makes a request to a Collector.
- The second time is the Collector's current time.
So ping time is simply the difference between the collector's current time minus the MOM's start time. That can also be affected by clock skew as well if the clocks are not in sync.
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