> -----Original Message----- > From: squid-users [mailto:squid-users-bounces@xxxxxxxxxxxxxxxxxxxxx] On > Behalf Of Amos Jeffries > Sent: Tuesday, October 27, 2015 5:57 AM > To: squid-users@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: Using Digests to reduce traffic between peers, > Parent - Sibling configuration question > > On 27/10/2015 5:14 p.m., Jester Purtteman wrote: > > So, here's my theory: Setup <expensive-server> so that it caches > > EVERYTHING, all of it, and catalogs it with this Digest. It doesn't > > expire anything, ever, the only way something gets released from that > > cache is when the drive starts running out of room. It's digest is > > then sent to <cheap-server>, which doesn't cache ANYTHING, NOTHING. > > When a request comes through from a client, <Expensive-Server> checks > > the refresh rules, and if it isn't too stale it gets served just like > > it does now, but if it IS expired, it then asks <Cheap-Server> "hey, > > how expired is this?" and <Cheap-Server> (which has all the bandwidth > > it could ever want) grabs the content, and digests it. If the digest > > for the new retrieval matches something in the digest sent by > > <expensive-server>, then <cheap-server> sends up a message that says > > "it's still fresh, the content was written by lazy people or idiots, carry on". > > > You just described what HTTP/1.1 revalidation requests do. In your logs as > REFRESH_*. Though they have to send HTTP headers around to get it to > work, which is a little more expensive than the Digest would be, the result is > far more reliable and accurate. > > > The Cache Digest is just a one-way hash of the URL entries in the cache > index. It is for reducing ICP queries to a peer proxy (ie the frontend cheap > server). If you dont have a cache at both end of the conection it is not useful. > And like ICP it is full of false matches when used with modern HTTP/1.1. > > Amos > What I'm hearing is, there are facilities for handling that already, don't crack open digest*.cc anytime soon :) Thank you Amos, both for the response, and for years of diligent effort. I have probably read hundreds if not thousands of your responses now, your efforts are appreciated by a quiet mob of people scratching their head in the wilderness. I have other questions, but they're unrelated, I'll let this thread go. _______________________________________________ squid-users mailing list squid-users@xxxxxxxxxxxxxxxxxxxxx http://lists.squid-cache.org/listinfo/squid-users
