> -----Original Message-----
> From: Pid [mailto:p...@pidster.com]
> Sent: Tuesday, November 15, 2011 9:09 AM
> To: Tomcat Users List
> Subject: Re: mod_jk Avoid loadbalancing
> 
> On 15/11/2011 15:00, Jeffrey Janner wrote:
> > Alexander -
> > From reading your emails, it sounds like you have the following setup
> >
> >                        F5 HW-balancer
> >                              |
> >                             / \
> >                            /   \     Level 1 balancing
> >                           /     \
> >                        HTTPD1  HTTPD2
> >                           |      |
> >                      ----------------   Level 2 balancing
> >                      |       |      |
> >                     TC1     TC2    TC3
> >
> > Is that correct?
> > You state that you want to eliminate Level 2.
> > However, from a performance standpoint, why would you?  Without the
> Level 2 balancing, it is conceivable that one of the 3 Tomcats could
> end up processing the bulk the JSP requests.
> 
> Why?
> 
> 
> p
To be honest, I don't think you can set up the Level 2 without some form of 
load-balancing, even if it is just round-robin.  But perhaps I'm not processing 
the full impact of how the whole structure will work, considering the OP wanted 
to eliminate the Level 2 LB.
I would think one would want the F5 to balance the loads on the HTTPD servers 
for that traffic, and let the HTTPD servers decide best use of the Tomcats to 
avoid overloading one (reason for LB).  Since the OP hasn't bothered to provide 
his physical or logical layout and his exact goals, I was postulating on theory 
alone.
However, his subsequent response makes it sound like he has 3 systems with 
HTTPD & Tomcat on each system.  It sounds like what he really wants is for 
HTTPD to forward only to Tomcat on the same server and let the F5 load balance 
and failover that setup.  Sounds reasonable, and fairly easy to set up.  
However, if he wants the above LOGICAL setup, then he needs to rethink his 
architecture.  For example, my suggestion at the beginning of this paragraph 
won't handle failover where only the Tomcat on server1 goes down, but the HTTPD 
is active.  Configuring for that eventuality takes a little more thought.  I've 
not done enough playing with the mod_jk config to be sure that is possible, but 
no one who is has weighed in on the specifics of his problem, probably because 
he hasn't fully explained the scenario he is trying to implement.
Jeff
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