On 23.07.2012 20:36, Carlucci, Tony wrote:
Hello, I’ve been trying to track down an intermittent problem with a Java web application that is running on tcServer fronted by Apache HTTP Server. We get intermittent “Server Unavailable / HTTP 500” errors, and when we do see them, there is the same set of log statements written to the Apache HTTP Server error log: [Mon Jul 23 10:03:15 2012] [error] (70014)End of file found: ajp_ilink_receive() can't receive header [Mon Jul 23 10:03:15 2012] [error] ajp_read_header: ajp_ilink_receive failed [Mon Jul 23 10:03:15 2012] [error] (120006)APR does not understand this error code: proxy: dialog to 127.0.0.1:7071 (127.0.0.1) failed We are not seeing any error messages in the tcServer logs. I believe the issue is with the mod_proxy_ajp module but it’s been very difficult tracking down what exactly the problem is. What’s interesting is that this Apache / tcServer configuration is used with other applications that work just fine and never have the intermittent 500 error. We also can run our application strictly in Tomcat (no Apache front) without any intermittent errors. We haven’t ruled out that there could be something in our Java application code that is causing this, in combination with the mod_proxy_ajp module, but we have hit a wall as to what this issue could be. Has anyone else experienced a similar intermittent issue combined with the above error messages? Below is a copy of the error log and some configuration settings.
You might want to check the following discussion thread: http://marc.info/?t=123905265500007&r=1&w=2 To actually narrow down the cause I would: - use ping as mentioned in the thread- check whether the timeout you have set on the Tomcat connector is roughly the same as used by mod_proxy_ajp - check whether it looks like happening mostly for the same URL, then it is more likely a servlet issue - if it happens often enough sniff the traffic between Apache and Tomcat and then check the packet details for one of the broken requests. For this to work you might need to move Tomcat away from localhost.
Regards, Rainer --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscribe@xxxxxxxxxxxxxxxx For additional commands, e-mail: users-help@xxxxxxxxxxxxxxxx
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