Re: [squid-users] Diagnosing Objects That Are Not Cached (squid/3.0.STABLE8)

Norbert Hoeller wrote:
> Although my squid server is only supporting three users, I am pleasantly surprised at the percentage of traffic handled by the cache. However, I think I can do better. Scanning the logs, I noticed a number of cases where the same files were resulting in a TCP_MISS/200 condition. A lot are due to '?'-strings in the URL, even though the content is not always dynamic (I am researching options).

Making sure you don't have...

acl QUERY urlpath_regex cgi-bin \?
cache deny QUERY

...in your squid.conf, in conjunction with the refresh_patterns you DO
have are about as far as you can go without starting to break standards.

> However, I see a fair number of cases where I would expect the object to be cached. Is there a process for diagnosing why squid thinks the object is not cache-able?
>

Up the debug_options for 22 and maybe 65. See
http://wiki.squid-cache.org/KnowledgeBase/DebugSections for a list.

> For example, from the access.log and store.log files:
>
> 1265776256.982 3934 10.1.2.123 TCP_MISS/200 861 GET http://www.facebook.com/images/loaders/indicator_blue_small.gif - DIRECT/66.220.146.18 image/gif
> 1265776281.912 370 10.1.2.123 TCP_MISS/200 861 GET http://www.facebook.com/images/loaders/indicator_blue_small.gif - DIRECT/66.220.146.18 image/gif
> 1265776294.352 407 10.1.2.123 TCP_MISS/200 861 GET http://www.facebook.com/images/loaders/indicator_blue_small.gif - DIRECT/66.220.146.18 image/gif
>
> 1265776256.982 RELEASE -1 FFFFFFFF 54F74EF7200473A70B1E94F452E355C0 200 -1 -1 1265776256 image/gif 522/522 GET http://www.facebook.com/images/loaders/indicator_blue_small.gif
> 1265776281.912 RELEASE -1 FFFFFFFF D50A66A7F3C5E849631BF132637A99A3 200 -1 -1 1265776281 image/gif 522/522 GET http://www.facebook.com/images/loaders/indicator_blue_small.gif
> 1265776294.352 RELEASE -1 FFFFFFFF 25AA53B40429083AF5B68BAF4A663EF0 200 -1 -1 1265776294 image/gif 522/522 GET http://www.facebook.com/images/loaders/indicator_blue_small.gif
>
> redbot.org returns:
>
> HTTP/1.1 200 OK
> Accept-Ranges: bytes
> Cache-Control: max-age=2592000
> Content-Type: image/gif
> Expires: Sat, 13 Mar 10 22:37:08 GMT
> X-Cnection: close
> Date: Thu, 11 Feb 2010 22:37:08 GMT
> Content-Length: 522
>
> General: The Expires header's value isn't a valid date.The Content-Length header is correct.The server's clock is correct.
> Caching: This response can be stored by any cache.This response is fresh until 4 weeks 2 days from now.This response can be served stale.
> Partial Content: A ranged request returned the full rather than partial content
>
> I am using a fairly vanilla squid.conf file, with the exception of some ad-blocking:
>
> #Suggested default:
> refresh_pattern ^ftp: 1440 20% 10080
> refresh_pattern ^gopher: 1440 0% 1440
> refresh_pattern (cgi-bin|\?) 0 0% 0
> refresh_pattern . 0 20% 4320
>
> Any suggestions would be greatly appreciated!
> Thanks, Norbert
>

Chris
Received on Fri Feb 12 2010 - 00:07:12 MST