Hi Squid Users, I use squid to accelerate my website, for example www.example.com. In the access.log, I found such 222.xx.yy.zz - - [22/Jul/2008:15:02:26 +0800] "GET http://www.example.com/ HTTP/1.1" 503 858 "-" "Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.2; .NET CLR 1.1.4322)" TCP_NEGATIVE_HIT:NONE Though I am sure that the backend web server is up and can provide service, still the browser got 503 Service Unavailable error display. I check the book 'Squid: The definitive guide', and found TCP_NEGATIVE_HIT When a request to an origin server results in an HTTP error, Squid may cache the response anyway. Repeated requests for these resources, within a short amount of time, result in negative hits. The negative_ttl directive controls the amount of time these errors may be cached. Also note that errors are cached only in memory and never written to disk. The following HTTP status codes may be negatively cached, subject to additional constraints: 204, 305, 400, 403, 404, 405, 414, 500, 501, 502, 503, 504. In Squid 2.6 configuration manual, it says, we can use negative_ttl to control Time-to-Live (TTL) for failed requests. My question is ,can we use negative_ttl 0 to disable caching of failed requests, so the following visitors will not get the TCP_NEGATIVE_HIT responses? Best regards, Xu Feng Shanghai,China
