Re: [squid-users] How do I stop the cache for a while

Ric Lonsdale wrote:
> Hi,
>
> Is it possible to stop squid from caching anything for a short period of
> time? I don't want to do this, but I'm being asked the question. Some guys
> want to fire requests for websites via the squid server, to the internet at
> set times during the day. They then want to fire exactly the same requests,
> but they want an anti-virus / malicious code server (Finjan), sitting in a
> DMZ, as the next hop after the requests have gone through squid and a
> firewall.
>
> They're doing this to see if the requests take significantly longer with the
> extra layer of security in the way, so don't want squid to send back already
> cached pages.
> If it is possible to stop squid from caching new requests, does it also mean
> it won't try to send existing cached pages back to the user?
>
> I told them I could use squidclient to delete entries from the cache, but
> they're talking about firing 1,000 URL's at it, which is obviously
> unmanageable.
>
> I don't want to delete the cache as it's 4.5gb.
>
> Any help appreciated.
>
> Thanks,
> Ric
>

Squid 2.6 has a "cache" directive
(http://www.squid-cache.org/Versions/v2/2.6/cfgman/cache.html, called
"no_cache" in 2.5) that, combined with ACLs will prevent caching of
requested pages. A side effect is that any matched objects that were
previously stored in the cache will be removed...

If it's really going to be set times of the day, using a time based acl
would be a good route to follow, but matching on source IP, user agent
string, destination domains, etc. would all work.

As a last resort, setting "cache deny all" and reloading Squid would
turn all caching off.

Chris
Received on Thu Nov 08 2007 - 15:41:48 MST