Re: [squid-users] My cache is far away from full. But lots of things get released. Why?

On Sunday 07 October 2001 09:24 pm, Joao Clemente wrote:
> When I looked up to store.log I was amazed... I have LOTS, the big
> majority of the entrances is like the following one :
>
> 1002503745.864 RELEASE -1 FFFFFFFF 5A788CE076480A75C1BC8627085DB3FA 304
> 1002503749 -1 -1 unknown 0/0 GET
> http://www.eu.mtnsms.com/images/yel/airborn.gif

This is a memory-only object (see FAQ).

> what means that these objects are not being cached... but why?
> Even if the web server says not to cache, shouldn't squid hold the
> objects and then sens a IMS packet to the server , trying to save

I believe that's exactly what it's doing (check the access log to verify
it's an TCP_REFRESH_HIT). It's constructing and sending an IMS
'sub-request' and ditching the result when it's done (since a 304 response
holds nothing of value).

> bandwidth ? This (the web server saying not to cache these objects) it's
> a wild gess for this behaviour, where can we get more info on why does
> this (almost all objects being released) happens?

You can usually check the cachability of objects by sending the request by
hand, such as

bash-2.05$ telnet www.eu.mtnsms.com 80
Trying 213.216.146.19...
Connected to 213.216.146.19.
Escape character is '^]'.
HEAD /images/yel/airborn.gif HTTP/1.0
Host: www.eu.mtnsms.com

(followed by a blank line).

You can tune the refresh_pattern lines to reduce how often the object is
checked, but you get more stale objects as a result.

        -- Brian
Received on Sun Oct 07 2001 - 21:29:33 MDT