Topic: mod_proxy_ajp + tomcat

[limittester]

Hello everyone!

I have already configured apache + tomcat ( using mod_jk ). The tomcat is deployed at / context and apache forwards all request ( except for static files which i have disable using JkUnMount ) to tomcat.

Specifically, I have the following lines in apache to let apache know to serve static files
JkUnMount /*.gif worker1

Now, after some bit of reading, I see that mod_proxy_ajp is another option over mod_jk. I have couple of questions on whether I need to migrate

1) Is mod_proxy_ajp faster that mod_jk ( any other assumptions / issues ) ?

2) Is it possible to achieve the above configuration ( that is, tomcat serving all request at www.mysite.com and apache serving only static files ) using mod_proxy_ajp ?

3) Not sure if this applies to this forum, but neways I am asking it: I also happen to see that tomcat supports NIO HTTP connectors. But since apache is the frontend server and all request goes to AJP connector ( port 8009), can I ever use NIO connectors in this mode ?

Thanks!

[tdonovan]

re: "1) Is mod_proxy_ajp faster"
Seems about the same to me. If there are performance differences they are very small.

re: "2) Is it possible ... apache serving only static files"
Yes. You will need to use ProxyPassMatch directives with the ! option to exclude your static files.
Be sure to put these before your regular ProxyPass directives in httpd.conf.

re: "3) can I ever use NIO connectors"
Since there is no NIO AJP connector, you could proxy from Apache to http://localhost:8080 instead of ajp://localhost to use the Tomcat NIO HTTP connector.
I'm not sure if this will really be better because the ajp: protocol is inherently more efficient than the http: protocol.

-tom-

[limittester]

thanks tom for reply!

So if ajp is better than NIO , what are the scenarios when anyone would use NIO connectors ( I see there must be some reason for apache to have built this in the new release ).

Does running tomcat standalone using NIO ( either port 80 / 8080 ) make this better ( i.e w/o apache ) ?

[tdonovan]

re: "ajp is better than NIO"
No, ajp is better than http. http+NIO is better than just http. I don't know if ajp is better than http+NIO.

re:"Does running tomcat standalone...make this better?"
The answer depends on too many things:

* Tomcat will be serving all the static content. NIO will help Tomcat to do this - but it still won't do it as well as Apache would.

* If you are limited by the speed of your physical network connection, a NIO connector won't make it go any faster than it goes with a regular connector.

* NIO is better if you have many (i.e. hundreds, thousands) of simultaneous connections, but still not better than Apache for the static content.

* NIO will make less difference if your Tomcat application(s) do a lot of work (database access, math calculations, etc.) to produce their responses.

In short - there is no "it is always better" answer about http+NIO vs. ajp. You really need to measure it with your own J2EE application(s) and users.

This test is worth doing if you have a very busy server. The choice could make a real difference if your application and user load just happens to take advantage of NIO.

re: "there must be some reason for apache to have built this"
It is always a big improvement for Tomcat sites that don't have/use Apache.
They will probably make an ajp+NIO connector eventually, but it is not as crucial a feature as the http+NIO connector.

-tom-