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wrapper.ping.timeout Property
wrapper.ping.timeout Property
Configuration Property Overview
wrapper.ping.timeout

Number of seconds to allow between the wrapper pinging the JVM and the response. 0 means never time out. Defaults to 30 seconds.

The ping timeout must be at least 5 seconds longer than the value of wrapper.ping.interval. The Wrapper will modify the value at run time if necessary to avoid problems.

In normal operation, the Wrapper pings the JVM once every 5 seconds to make sure that its process has not frozen up. The ping timeout is the amount of time to allow for a response from the JVM before the Wrapper assumes that it is hung and restarts it.

This same property also controls the amount of time that the JVM will allow to pass without being pinged by the Wrapper. If the Wrapper does not ping the JVM for longer than the specified timeout, it will exit allowing the Wrapper to resynch by launching a new JVM. This also makes sure that the JVM will exit if the Wrapper process is terminated abnormally. (By killing the Wrapper process in the Windows Task Manager, or using kill -9 on Unix systems.)

With the addition of the wrapper.cpu.timeout property, there is now almost no reason why you should ever need to change this property. The only reasons why you should be getting ping timeouts are if the system is under heavy load or if the JVM is really hung. The CPU timeout should now detect any problems in with CPU.

Example:
wrapper.ping.timeout=30

WARNING

While the ability is there. Be aware that setting this property to 0 or some large value will mean that the Wrapper's ability to detect a JVM hang as it is running will be disabled.

Also note that if the Wrapper process is killed abnormally or God forbid crashes, then the JVM will never attempt to resynch with the Wrapper. If the Wrapper was running as an NT service at the time, it may be necessary to then reboot the machine to stop Java process. With normal ping timeouts, the JVM would exit on its own after a few seconds.

by Leif Mortenson

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