On 25/07/2012 14:23, Carlucci, Tony wrote: >> -----Original Message----- >> From: Rainer Jung [mailto:rainer.jung@xxxxxxxxxxx] >> Sent: Wednesday, July 25, 2012 5:00 AM >> To: users@xxxxxxxxxxxxxxxx >> Subject: Re: Intermittent mod_proxy_ajp error - APR does not >> understand this error code: proxy: dialog >> >> 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. >> > Thanks for the suggestions Rainer, I'll give these a try. > > Tony forget mod_proxy_ajp, use mod_jk -- Simone Caruso IT Consultant +39 349 65 90 805 --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscribe@xxxxxxxxxxxxxxxx For additional commands, e-mail: users-help@xxxxxxxxxxxxxxxx
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