Amos Jeffries wrote: > > Alex Rousskov wrote: > >> On 10/10/2017 07:50 PM, Victor Sudakov wrote: > >> > >>> When updating several almost identical FreeBSD hosts via a > >>> squid-3.5.27 proxy, I expect to see lots of HITs, because the patches > >>> on the update server should be identical too. > >>> > >>> However, I see lots of TCP_REFRESH_UNMODIFIED lines, and only > >>> occasional HIT statuses. > >> > >> > >> There are many kinds of "hits": > >> > >> * If your primary concern is data transfer/bandwidth usage, then you > >> should focus on so called byte hits. TCP_REFRESH_UNMODIFIED is > >> essentially one of those because the origin server sends a tiny > >> headers-only response to Squid. > > > > My primary concern is bandwidth usage. You are saying that the > > TCP_REFRESH_UNMODIFIED transaction means that the bulk of the data is > > not transferred from Webserver to Squid, only the headers are fetched? > > Yes. > > > > > If you look at this line: > > > > 1507630625.515 448 212.73.124.12 TCP_REFRESH_UNMODIFIED/200 980593 GET http://update6.freebsd.org/to-10.4-RELEASE/i386/bp/1195d725efce75f0db6317f507d8a9514f35613c7466673a86db23100bd6fa77-c4150431df5b14b15546b3db5e30f2bd2c35d6d52812f057dc101fab20847324 - HIER_DIRECT/198.148.79.66 application/octet-stream > > > > There cannot be 980593 bytes of headers? What kind of gigantic header > > does it make? > > > > That is header only between Squid and server (REFRESH_UNMODIFIED), with > full object delivered to the client (final status "200"). I see now, the 980593 bytes in the log is between Squid and client, not between Squid and Webserver. > >> > >> According to your pasted log and HTTP messages, the GET request URL that > >> resulted an "X-Cache-Lookup: MISS" response header does not match any of > >> the logged URLs; even the host part of the URL does not match. > > > > Of course, there are just unrelated examples. There are thousands of > > fetches from update*.freebsd.org > > So you just posted them to waste everybody on this lists bandwidth? Hmm, well, no. Consider them two separate examples: a) a sample log output and b) a sample HTTP session. Both were necessary for illustrating the question. I never thought someone would try to juxtapose them. > Thanks, and kind of ironic given your "problem". About 30 lines of logs and Wireshark output surely wasted the lists bandwidth. Sorry about that. > > > > >> To be sure that you are comparing apples to apples, you would need > >> to log the X-Cache-Lookup response header to access.log (or enable > >> ALL,2 debugging to see headers and/or collect packet traces). > > > > I don't think the freebsd-update cares about the X-Cache-Lookup > > response, I'm just trying to save bandwidth and don't quite like the > > result. > > > > The X-Cache* headers are debug output from Squid. Of course the updater > software does not care about it ... you do, sort of anyway since it > shows whether server bandwidth was involved. They do not show REFRESH, > so MISS means a server was contacted for _something_ and HIT means local > cache only was used. Thank you for clarification. I will not fear the TCP_REFRESH_UNMODIFIEDs any more. -- Victor Sudakov, VAS4-RIPE, VAS47-RIPN AS43859 _______________________________________________ squid-users mailing list squid-users@xxxxxxxxxxxxxxxxxxxxx http://lists.squid-cache.org/listinfo/squid-users
