Re: mod_proxy_ajp connections erratic

[Craig Main <cmain@xxxxxxxxx>]

Thanks Andre, 

I am using apache to connect to 10 tomcat instances using the ajp connector with load balancing and sticky sessions.

Apache: 
Load [root@lt-webportal-01:~]  # /opt/apache/bin/apachectl -V
Server version: Apache/2.2.9 (Unix)
Server built:   Sep  6 2008 15:33:44
Server's Module Magic Number: 20051115:15
Server loaded:  APR 1.3.0, APR-Util 1.3.0
Compiled using: APR 1.3.0, APR-Util 1.3.0
Architecture:   64-bit
Server MPM:     Prefork
  threaded:     no
    forked:     yes (variable process count)
Server compiled with....
 -D APACHE_MPM_DIR="server/mpm/prefork"
 -D APR_HAS_SENDFILE
 -D APR_HAS_MMAP
 -D APR_HAVE_IPV6 (IPv4-mapped addresses enabled)
 -D APR_USE_SYSVSEM_SERIALIZE
 -D APR_USE_PTHREAD_SERIALIZE
 -D SINGLE_LISTEN_UNSERIALIZED_ACCEPT
 -D APR_HAS_OTHER_CHILD
 -D AP_HAVE_RELIABLE_PIPED_LOGS
 -D DYNAMIC_MODULE_LIMIT=128
 -D HTTPD_ROOT="/opt/http-2.2.9"
 -D SUEXEC_BIN="/opt/http-2.2.9/bin/suexec"
 -D DEFAULT_PIDLOG="logs/httpd.pid"
 -D DEFAULT_SCOREBOARD="logs/apache_runtime_status"
 -D DEFAULT_LOCKFILE="logs/accept.lock"
 -D DEFAULT_ERRORLOG="logs/error_log"
 -D AP_TYPES_CONFIG_FILE="/opt/etc/httpd/mime.types"
 -D SERVER_CONFIG_FILE="/opt/etc/httpd/httpd.conf"

Tomcat: apache-tomcat-6.0.18

Platform: CentOS 5.2 64bit


The problem points to the ajp connection as we have done the following tests:

1) Load tested http with our static content. - Good Response times
2) Load tested with the tomcat ajp load balancing to 10 tomcat instances:
        * When we test the site's static content, the speed is fine
        * When we test the site's pages that go to tomcat, we see the same page returning sometimes fast, and other times slow.
        * If we test connecting to the tomcat via it's http connector from the command line, the speed is fine under load.
        * If we test connecting to the apache requesting the tomcat pages, some of the requests are returned quickly, others are slow.
3) At first we thought it could be an specific instance of Tomcat, but on investigation, one request to a particular instance was fast, and others we slow to the same instance.

Please let me know if you need more information.

Thanks
Craig 


On Thu, 2009-04-23 at 08:44 +0200, André Warnier wrote:
> Craig Main wrote:
> > Hi All,
> > 
> > I am using apache to from 10 tomcat instances using the ajp connector
> > with load balancing and sticky sessions.
>
> Can you reread that phrase ?
> Which versions of Apache, Tomcat, the connector ?
> On which platform ?
> How do you determine that some connections are erratic/slow ?
>
> Not all of the above may be necessary in the end, but by providing this 
> upfront you save people from asking, thus increasing your own chances of 
> not being ignored and getting a helpful answer.
>
>
>
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