Hi, I'm trying to set up two squid siblings in front of lighttpd as reverse proxies and have a question about some behavior I'm seeing. Squid versions are 2.7.STABLE7-1~bpo50+1 from the debian backports repository. My goal is to create a setup with two cache siblings and one origin server (lighttpd) where no duplicate cached entries between siblings exist. I am getting these TCP_HIT/504's and I can't understand why they are happening. When I do a refresh in firefox and request a picture from sibling1, requested before on sibling2, I see the following: sibling1 is 5.5.5.5 - The original request on sibling 1: 1269431848.626 4 1.1.1.1 TCP_MISS/304 378 GET http://pictures.something.com/pics/d/3/c/picture.jpg - DEFAULT_PARENT/pict-dev image/jpeg - A UDP_HIT occurs on sibling2, sibling1 tries to fetch the file but it received a 504 instead (excerpt below). 269431848.881 0 5.5.5.5 UDP_HIT/000 76 ICP_QUERY http://pictures.something.com/pics/d/3/c/picture.jpg - NONE/- - 1269431848.883 1 5.5.5.5 TCP_HIT/504 1752 GET http://pictures.something.com/pics/d/3/c/picture.jpg - NONE/- text/html ----start---- HTTP/1.0 504 Gateway Time-out Expires: Wed, 24 Mar 2010 09:55:19 GMT X-Squid-Error: ERR_ONLY_IF_CACHED_MISS 0 Age: 1269424520 Warning: 113 localhost (squid/3.0.STABLE8) This cache hit is still fresh and more than 1 day old X-Cache: HIT from localhost X-Cache-Lookup: HIT from localhost:80 The requested URL could not be retrieved Valid document was not found in the cache and 'only-if-cached' directive was specified. You have issued a request with a 'only-if-cached' cache control directive. The document was not found in the cache, or it required revalidation prohibited by 'only-if-cached' directive. ----end---- Why does sibling2 respond with a UDP_HIT but then sends a 504 error page to sibling1 when sibling1 tries to fetch the picture? Is this normal behavior or am I doing something wrong here? Please see my squid.conf below, suggestions are very much appreciated and thanks in advance. acl all src all acl manager proto cache_object acl localhost src 127.0.0.1/32 acl to_localhost dst 127.0.0.0/8 acl SSL_ports port 443 acl Safe_ports port 80 #http acl Safe_ports port 21 #ftp acl Safe_ports port 443 #https acl Safe_ports port 70 #gopher acl Safe_ports port 210 #wais acl Safe_ports port 1025-65535 #unregistered ports acl Safe_ports port 280 #http-mgmt acl Safe_ports port 488 #gss-http acl Safe_ports port 591 #filemaker acl Safe_ports port 777 #multiling http acl CONNECT method CONNECT acl sites dstdomain pictures.something.com acl siblings src 6.6.6.6 cache_peer 4.4.4.4 parent 80 0 default no-query no-digest originserver name=lighttpd-server login=PASS cache_peer 6.6.6.6 sibling 80 9832 proxy-only name=sibling2 cache_peer_access lighttpd-server allow sites cache_peer_access sibling2 allow sites http_access allow sites http_access allow siblings http_access allow manager localhost http_access deny manager http_access deny !Safe_ports http_access deny CONNECT !SSL_ports http_access allow localhost http_access deny all icp_access allow siblings icp_access deny all htcp_access deny all miss_access deny siblings http_port 80 act-as-origin accel vhost icp_port 9832 access_log /var/log/squid/access.log debug_options ALL,3 cache_mgr cachmgr@xxxxxxxxxx cache_dir aufs /var/spool/squid 4000 32 128 refresh_pattern ^ftp: 1440 20% 10080 refresh_pattern ^gopher: 1440 0% 1440 refresh_pattern -i (/cgi-bin/|\?) 0 0% 0 refresh_pattern . 0 20% 4320
