A very high volume of messages written to the WebSphere Liberty messages.log has the ability to severely impact the performance of a server.

It has been found that the writing of a very high volume of messages to the WebSphere Liberty messages.log has the ability to severely impact the performance of a server. In this case, the z/OS Connect product running within a Liberty server was writing millions of GMOMW0005E messages to messages.log. The attempts to write all these messages to a file caused contention for the file, this in turn cause the pthread_yield function to be called. The pthread_yield processing involves setting a STIMER and as STIMER is native z/OS function, zIIP eligible work had wait for the STIMER processing to run on CPs. This had a catastrophic impact on the performance of the system and it was very difficult to identify the root cause.

It has also been reported that files that the messages are written to (trace.log or messages.log) can fill up the zFS if the rate is high enough and the server is up long enough

The existing Liberty function "hideMessage" causes messages to be redirected from messages.log to trace.log, but that does not help in this scenario as it redirects the messages from messages.log to trace.log and the messages are still written to a file.

While the problem was observed with z/OS Connect messages, any message that goes through the Liberty logging/tracing mechanism has the ability to trigger this problem.

We would like a solution which would avoid these performance and file size issues.

A possible solution would be an option which allows any messages reported via the Liberty tracing and logging mechanism to be completely suppressed. A configuration that would allow a number of the messages to be logged until a threashold is reached, so that any failures are not totally silent, but are not allowed to cause the performance problems might be useful.

There could be other routes to a resolution.