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From <Gerhardus.Geldenh...@gta-travel.com>
Subject RE: apache getting in "sending reply" state when connecting to tomcat
Date Wed, 29 Aug 2007 11:54:06 GMT
Hi
I forgot to add, that our solution at the moment is to restart apache
which 9 out of 10 times solves the problems. We see connections reach
almost 250 (248,249) per tomcat server on the apache box. After restart
this drops down 

We also only see the problem when we are experiencing heavy load and it
happens very quickly when it does. 

Regards 

> -----Original Message-----
> From: Gerhardus Geldenhuis (GTA-LON) 
> Sent: 29 August 2007 11:47
> To: users@tomcat.apache.org
> Subject: apache getting in "sending reply" state when 
> connecting to tomcat
> 
> Hi
> I'm kind of between a rock and a hard place.
>  
> We have a problem in our production system that occurs quite 
> regularly.
> Apache's connections all get into a Sending Reply ( W ) state 
> and which makes the application unresponsive.
> We have an apache 2.0.52 fronting 12 tomcat 5.5 all on CentOS 
> 4.5 using mod_jk with, dare is say it, default settings. :-( 
> We have a stripped down apache installed on each Tomcat blade 
> and what is interesting is that when we reach this stage of 
> all connections in "W" state we can access the application 
> using the local apache on the tomcat blade using port 8080 
> but not access it on port 8009 using the local apache on the 
> tomcat blade. This to me points to a connector problem.
>  
> I believe that the problem is related to our mod_jk settings 
> or lack there off and also the version we are using.
>  
> What makes matters a bit difficult for me is that we are 
> unable to recreate the problems we are seeing in production 
> on our test systems which makes it very difficult to push out 
> changes to production.
> Management is quite strict in allowing production changes, 
> which is understandable because downtime is expensive.
>  
> We are using
> mod_jk-1.2.22-2.0.52-linux-x86_64.so
> httpd-2.0.52-28.ent prefork
> Tomcat 5.5
> 
> Questions:
> ~~~~~~~~~~
> * Do you agree that it is mod_jk settings?
> * What more information do I need or should look at to 
> determine problems.( The developers regularly scrutinize 
> thread dumps we make)
> * mod_jk docs says: mod_jk-1.2.25-httpd-2.0.59.so is for 
> Apache 2.0.x and works with Apache 2.0.59 and later,  will 
> using httpd-2.0.52-28.ent be a problem?
> 
>  
> Settings
> ~~~~~~
>  
> httpd.conf
> ~~~~~~~~~~
> <IfModule prefork.c>
> StartServers       8
> MinSpareServers    8
> MaxSpareServers   300
> ServerLimit      575
> MaxClients       575
> MaxRequestsPerChild  4000
> 
> workers.properties
> ~~~~~~~~~~~~~~~~~~
> # Worker list
> worker.list=xml-gta,jkstatus
> 
> # Worker definitions
> worker.xml-gta.type=lb
> worker.xml-gta.method=Busyness
> worker.xml-gta.balanced_workers=
> lonstct01agx,lonstct01bgx,lonstct01cgx,,lonstct01dgx,lonstct01
> egx,lonstc
> t01fgx,lonstct01ggx,lonstct01hgx,lonstct01igx,lonstct01jgx,lon
> stct01kgx,
> lonstct01lgx
> worker.jkstatus.type=status
> 
> # Balance workers
> worker.lonstct01agx.port=8009
> worker.lonstct01agx.host=xx.xx.xx.xx
> worker.lonstct01agx.type=ajp13
> worker.lonstct01agx.lbfactor=1
> 
> ...
> 
> worker.lonstct01lgx.port=8009
> worker.lonstct01lgx.host=xx.xx.xx.xx
> worker.lonstct01lgx.type=ajp13
> worker.lonstct01lgx.lbfactor=1
>  
> server.xml
> ~~~~~~~~~~
> <Connector port="8009"
> enableLookups="false" redirectPort="8443" protocol="AJP/1.3" />
> 
> 
> Suggested Changes I want to make (but still need approval 
> for) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> Upgrade to mod_jk .25
> 
> Change workers.properties to:
> 
> workers.properties
> ~~~~~~~~~~~~~~~~~~
> # Worker list
> worker.list=xml-oct-gta,jkstatus
> 
> # Worker definitions
> worker.xml-oct-gta.type=lb
> worker.xml-oct-gta.method=Busyness
> worker.xml-oct-gta.balance_workers=longtct02c,longtct02d
> worker.xml-oct-gta.lock=Pessimistic
> worker.xml-oct-gta.max_reply_timeouts=10
> 
> worker.jkstatus.type=status
> 
> 
> # Worker Template
> worker.reference.port=8009
> worker.reference.type=ajp13
> worker.reference.lbfactor=1
> worker.reference.socket_timeout=60
> worker.reference.socket_keepalive=true
> worker.reference.connect_timeout=500
> worker.reference.prepost_timeout=500
> worker.reference.reply_timeout=32000
> worker.reference.recovery_options=27
> # 16 8 2 1
> worker.reference.retries=12 #
> 
> # Balance workers
> worker.longtct02c.reference=worker.reference
> worker.longtct02c.host=xx.xx.xx.xx
> ... (there are 10 other servers not listed here for space saving
> purposes)
> worker.longtct02d.reference=worker.reference
> worker.longtct02d.host=xx.xx.xx.xx
> 
> Regards
> 
> ______________________________________________________________________
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