PEGA0055 alert: Clock drift exceeded the configured time threshold
A PEGA0055 alert occurs when the clock drift in any of the participating nodes in a multinode cluster exceeds the configured time threshold.
In most hardware platforms, clocks run at different rates, depending on CPU loading and other internal factors. Usually, a Network Time Protocol (NTP) service or daemon runs to ensure that the clocks are corrected by means of a standard external Internet time service, for example, nist.gov.
On the Pega 7 Platform, the clock drift is measured against the average time of the clocks in the cluster. When the alert is triggered, an error is reported to the log file on the node that detected the issue.
Example message text
The alert log message indicates that the clock drift in one of the cluster's nodes has exceeded the configured time threshold in seconds. The message displays the number of seconds by which the clock has drifted from the average time of the clocks in the cluster, as shown in the following example:
This node's [node-identifier] clock has drifted beyond configured threshold [10 sec]; the actual delta is 10.25 seconds.
Default prconfig.xml setting
The threshold is established in the following prconfig.xml file setting:
<env name="alerts/cluster/clockdeltathreshold" value="10" />
Reasons for the alert
A large number of PEGA0055 messages in your alert log indicates a problem with the configuration of the system clock on one or more servers, resulting in a significant clock drift. The problem might be caused by the failure of the network time protocol to synchronize the clocks.
You can check the following items:
- Server configuration – A heavy CPU load on one or more servers can cause the clock to drift excessively.
- Excessive load on the servers – Transient loads can cause the clock to slowly drift. A correctly configured Network Time Protocol (NTP) daemon corrects this problem. Check the server or servers that are being reported for the root cause of the clock drift.