[Gllug] Single IP, HTTP accelerator fronting multiple webservers

[Daniel P. Berrange]

On Thu, Feb 23, 2006 at 07:05:07PM +0000, Richard Jones wrote:
> On Thu, Feb 23, 2006 at 07:01:16PM +0000, Daniel P. Berrange wrote:
> > It works very well - every single APLAWS+ site is running SQUID in
> > front of the Apache+Java Appserver layer to provide acceleration.
> > If you want redundancy you can setup multiple SQUID servers in all
> > sorts of peering arrangements.
> 
> But do you have one SQUID fronting multiple servers, physical or
> virtual?  And routing requests based on the Host header?

We've done many different combinations before, depending on the 
deployment scenario. Some examples:

 eg mod_caucho apache plugin for load balancing / failover.

    /--> resin app server 1  -\
  Db                           apache -> squid -> internet
    \--> resin app server 2  -/

 eg RH Cluster Suite doing load balancing / failover

    /--> tomcat app server 1 ->  apache -> squid  -\
  Db                                                LVS =-> internet
    \--> tomcat app server 2 ->  apache -> squid  -/

 eg Network switch for load balancing

    /--> tomcat app server 1 ->  apache -> squid  -\
  Db                                                --> internet
    \--> tomcat app server 2 ->  apache -> squid  -/

The only time we had trouble with SQUID, was when one apache server 
was accepting requests, but then not processsing them. So squid got
blocked up with lots of pending requests & stopped accepting new 
stuff, even though the second apache was still capable of working.

Dan.
-- 
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|=-   berrange at redhat.com  -  Daniel Berrange  -  dan at berrange.com    -=|
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