infrastructure setup using ESI

David Birdsong david.birdsong at
Thu Oct 21 23:41:58 CEST 2010

Most load balancers have a hashing lb method.  Hash on something int the
request and only send that traffic to a specific *alive* varnish instance.

On Oct 21, 2010 2:16 PM, "Gresens, August" <AGresens at> wrote:


Varnish is a key part of a new set of apps we are building - the ESI feature
in particular is something we want to take advantage of extensively.

Where does Varnish typically reside in the network architecture? I would
imagine in a scenario in which we would be using ESI, we would want Varnish
in front of the application load balancers. In this way, Varnish would be
the primary page assembler. We would likely run an HA setup for fault

We were also considering if Varnish could be used much farther downstream –
in between the load balancer and the application. We thought is might
provide for more fault tolerance, but it seems the disadvantage would be
that there would be a separate cached copy in each redundant varnish
instance, and with ESI secondary requests would be made back out to the same
web server potentially, setting up a feed back loop that could cause

Thanks for your responses in advance.


August Gresens
Director of Technology, eScholastic

Scholastic Inc.
557 Broadway, NY, NY 10012

Email :: agresens at
Phone :: 917 363 3662

varnish-misc mailing list
varnish-misc at
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <>

More information about the varnish-misc mailing list