Clock Skew warnings logged on a Standalone Enterprise Manager. Warn Manager.Clock

Document ID : KB000048415
Last Modified Date : 14/02/2018
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Description:

When an Enterprise Manager is running in Standalone mode and is not part of a Cluster, the following Clock Skew warning may appear in the EM log:

[WARN] [Manager.Clock] The system clock, previously set at 1214938515132 mS, has been reset to 1214938515131 mS. The EM will now pause to allow the clock to catch up, so as to maintain internal consistency of time-oriented metric data.

Solution:

The Enterprise Manager issues this warning to indicate that the system clock was reset on the server where the EM is installed. The reset itself is not a function of APM, but occurs during synchronization of the EM server with an NTP server.

This message is not related to synchronization between multiple EMs in an APM Cluster, though the same message will also be logged for EMs in a Cluster where time synchronization has occurred.

The Enterprise Manager property:


 	introscope.enterprisemanager.clock.skewsuppresswarn=0 

may be set in the IntroscopeEnterpriseManager.properties file to suppress these messages for clock resets of less than the number of milliseconds you specify.

When not set, the default value is 0, meaning that all warnings of this type will be logged. By setting this property to a larger value, any clock regression that is less than this property in milliseconds will be suppressed and will not appear in the log.

Note that the Enterprise Manager delays the harvest cycle for clock resets whether the warning message is logged or not.

The advantage to setting this property is to prevent clock reset messages from flooding the log on systems where the system clock drifts frequently from the NTP time server.