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From Dimitar Georgievski <>
Subject Re: Reuse mod ajp proxy connections
Date Thu, 20 Oct 2011 15:37:39 GMT
On Wed, Oct 19, 2011 at 10:27 AM, Christopher Schultz <> wrote:

> Hash: SHA1
> Dimitar,
> On 10/18/2011 10:50 PM, Dimitar Georgievski wrote:
> >> SetEnv force-proxy-request-1.0 1 SetEnv proxy-nokeepalive 1
> > This setting should control the mod_http_proxy connections. I
> > forgot to mention this Apache server does that.
My reading suggests that it controls mod_proxy, which should be the
> same for all mod_proxy_*. The documentation for mod_proxy_ajp is
> woefully slim. Sure, you can learn all about the AJP protocol, just
> not how to configure the proxy in httpd.conf :(
> We have started series of tests to determine the effect of the following

   1. Upgrade Apache to 2.2.21 (the latest)
   2. Upgrade Tomcat to 5.5.34 (the latest in the 5.x series)
   3. Remove *SetEnv force-proxy-request-1.0 1 SetEnv proxy-nokeepalive 1*

 It will take a while to complete these tests whch has to do with our test
methodologies, which could be summarized as make one change and repeat the
baseline test at least twice.

> I'll definitely take out these settings, because the http proxy
> > connections should also be persistent.
> Okay. Did it work? Seems like a simple test to make.
> > Regarding the upgrade of the Tomcat server we might not be able to
> > do that. The application hosted by Tomcat has dependency on the
> > Tomcat 5.5.x version which limits our options. I'll need to
> > determine yet which version would be compliant with our
> > application.
> If you have dependencies on Tomcat code, it's best to replace those
> with standards-compliant code. Maybe we could help with that kind of
> thing.
> As for 5.5 -> 6.0 -> 7.0 upgrades, I have recent done that exact thing
> and have had no problems whatsoever. Tomcat *should* be
> backward-compatible with previous releases, but there are some gotchas
> to be found when the TC code has become more spec-compliant or more
> cranky about certain bad configurations that it used to allow.
> As with any upgrade, always read the release notes / changelog carefully.

The application that is deployed on Tomcat 5.x is called Sakai ( From what I know it has strict dependencies on
the Tomcat version. We started reviewing the requirements for the migration
to Tomcat 6.x but this will take a while, probably months to complete.


> I am also considering to install Apache Portable Runtime to
> > improve connectors performance and determine its effects on the
> > persistence of the proxy connections. What do you think?
> If you expect high concurrency, try using the NIO connector(s): they
> should scale better and have the advantage of being all Java, so you
> have less risk of crashing your JVM if something goes wrong (though
> the APR AJP connector /is/ pretty rock-solid).
> This is also in our test plans but this change has to wait on the result of
the servers upgrade tests. Moving to NIO or APR seems a sensible thing to

The Apache server does more than being a reverse proxy for this Tomcat
server and couldn't be removed from the server configuration of this



> - -chris
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