Q: Caching Hierachy

[Christoph]

On Wed, Jul 04, 2007 at 12:52:43AM -0700, Ask Bjrn Hansen wrote:
> 
> On Jul 4, 2007, at 12:23 AM, Christoph wrote:
> 
> >I need to build a hierachical caching plattform. The Goal is, to have
> >multiple frontends that will expire in sync.
> [...]
> >Is this possible with varnish?
> 
> I haven't tried it with varnish, but I think it should work if you  
> use "Expires: ..." rather than "Cache-Control: max-age=..." to  
> specify the TTL.

The backend (apache) will always set a relative Expires Headers
(access+300seconds)

> 
> I'm curious why you want to use that setup though.  It seems like you  
> are just introducing an extra single point of failure and wasting a  
> lot of memory.    There are at least a couple of different setups  
> that seems more reasonable.    What are you trying to accomplish?

Goal is to synchronize all cachers. Have content expire at the same time
on all cachers. All cachers will be used in a round-robin-DNS entry. As
users are not bound to always hit the same Cacher. if a user hits reload
he might get jumping-content when switching between cachers. 

Could you hint me on a setup to reach this goal?

Greetings
   Christoph