Our current production web environment uses:
- Web Server: Netscape iPlanet v4.1 (don’t laugh!)
- Servlet Container: Tomcat 6.0.32
Both running SunOS 5.9 (Solaris 9?) on separate servers.
We have noticed that (apparently) randomly, the applications running on Tomcat appear to be unavailable. Further investigation appears to show that the AJP connections from the webserver appear to be blocked – or at least the web-server is unable to successfully forward requests to Tomcat.
Has anyone else experienced (and fixed) such issues with iPlanet/Tomcat?
NB: We realise that iPlanet v4.1 is somewhat ancient, and it is being replaced with Apache HTTP Server, however not just yet.
We have managed to solve our issue. For anyone experiencing the same issue, as described above, the problem is that there is a bug in the iPlanet mod_jk connector (v1.2.22), which amongst other things, does not reuse existing connections, instead it creates new connections for each request.
The solution is to obtain a more up-to-date driver (v1.2.32 at time of writing), which fixes this issue, and others, making the connector not only much more robust, but also increases throughput by more than 4 times!
The updated driver can be found on the Tomcat site.
For users who are not using Windows or Netware, you will need to build you own driver, which depending on the level of your C knowledge, may be a little tricky, as we had to modify the source several times to add missing headers.
Hopefully, this will help somebody out there!