RE: [squid-users] Dual Cache

> Is it possible to setup two squid servers, and split traffic
> accross these?
>
There are several ways to achieve such traffic sharing, ranging widely
in complexity and efficiency.

I have experience with some of these at a large site - 25,000 desktops
distributed all over Australia with 24 production squid caches and about
450 local office Bordermanager caches in a four or five level hierarchy
largely to save WAN bandwidth.

Between the WAN and the Internet we had three levels of cache involving
six squid boxen which were at the two lower levels each configured to
have a default parent and a backup parent. The WAN was physically and
logically split into two so that one top WAN level cache did each side
of this split with the other being the backup.

The clients in the central office in Canberra used a rotation scheme in
their proxy.pac to divide them between the cache pairs (on a per session
basis.) This resulted in all the traffic being fairly evenly split
between these six caches.

I haven't gone into great detail here as the situation was complicated
by the fact that we had a DR site in Sydney (including backup
firewall/DMZ) which was on one side of the WAN, and a complex dodgy
split DNS system.

Another solution is to use a level 4 switch such as the Cisco stuff or
BigIP.

Lastly you can use DNS tricks to split the traffic (one name with two IP
addresses.)

For a small to medium site I would recommend the proxy.pac solution
which is fairly easy to implement if you know some javascript.

> Is it possible to configure the one cache to be used for
> "browsing" and the second for "downloads"?
>
You can only do this with a two-level cache system and ACLs at the lower
level or by some fancy stuff in proxy.pac.

Michael Lightfoot
Unix Consultant
ISG Host Systems
Comcare
+61 2 62750680
Apologies for the rubbish that follows...
 
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Received on Tue Oct 29 2002 - 16:26:12 MST