On Mon, Sep 29, 2008 at 4:19 AM, Gordon Mohr <gojomo@xxxxxxxxxxx> wrote: > Using 2.6.14-1ubuntu2 in an reverse/accelerator setup. > > URLs I hope to be cached aren't, even after adjusting passed headers. > > For example, I request an URL with FireFox, get the expected MISS. Then > request same URL with IE, get unexpected MISS when I'd like a HIT. Then > request same URL with Chrome, get MISS instead of HIT. Finally, request with > Safari, finally get a HIT. > > I gather that the key variable is the differing Accept-Encoding headers: > > Firefox: gzip,deflate > IE: gzip, deflate > Chrome: gzip,deflate,bzip2 > Safari: gzip, deflate (same as IE, hence the HIT) > > My theory was that stripping the varied header values and replacing them > with the lowest-common-denominator (and the only variant ever returned by > the parent server) could help. So I added the following to my squid > configuration: > > header_access Accept-Encoding deny all > header_replace Accept-Encoding gzip > > However, this has not changed the HIT/MISS pattern at all. > > Any other ideas for letting all these browsers share the same cached > version? If the HTTP response includes "Vary: User-Agent" then Squid will give HIT only for same User-Agent, check your case. > > (Bonus question: My inner-server's 404 responses include a 24-hour Expires > header. Will these be cached by squid for the declared period or the shorter > negative-ttl? The info at > <http://wiki.squid-cache.org/SquidFaq/InnerWorkings#head-aed2acb07aed79ef1f7a590447b6a45a8dd8e7d1> > is unclear which wins.) > > - Gordon @ IA > > Error caching is called negative cache, and depends on "negative_ttl" parameter in squid.conf which default to 5 minutes, so the 404 will be cached only 5 minutes by default. Itzcak
