Re: Sibling --> Parent Relations & Multiple Hosts

From: Graham Toal <>
Date: Thu, 8 May 1997 14:22:21 -0500 (CDT)

> If the heavy weight parent does not have the object in cache, since it is an
> accelerator, will it get the object from the httpd server it accelerates for,
> or will it reply to the front end server that it does not have it in cache
> which would then make the front end cache request it from the lighter weight
> server?

The first squid asks all its parents/siblings if they have the page,
then it decides which parent to fetch it from or go directly. I don't
think the accelerator cache will say it has it if it isn't in the
cache, even though it knows it can get it quickly. It won't actually
fetch it until the second unconditional GET request arrives.

> Question 2:
> Does a parent have to be a "cache"? Or can you define a parent that is just an
> httpd server?

Well, I think when squid asks a parent for a page it sends the stuff as part of the URL, so a plain http server probably
wouldn't work, but one like CERN which can also be a proxy probably would.

> Question 3:
> Along the lines of question number 2, is it possible to configure Squid to act
> as an httpd accelerator for multiple sites (physically independent not

Yes. The documentation on this changed recently. The older release i was
using said the accelerator had to access the same machine; in the later
release I just fetched this is no longer true apparently. Certainly if
you are using the redirector it is definitely not true.

> "virtual" sites), and you could define "weights" for the different sites it is
> accelerating for? So when a request comes into Squid for an object, if the
> object was not in cache it would first try to retrieve it from the heavy
> weighted httpd server? Then if that server did not have it, or timed out it
> would attempt to get it from the next heavyiest weighted httpd server?

That's done automatically by squid's page fulfilment algorithm. You can
give weights to the servers in squid.conf

> TAG woked just fine, thank you "So K T, CUHK" for the help! Yet can you
> define Squid to accelerate for different sites that are not physically on the
> same system and are not "virtual sites".

Yes, using the redirector. I set up one like that last night.


[Correct me someone more knowlegable if I'm wrong here.]
Received on Thu May 08 1997 - 12:21:01 MDT

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