Re: [squid-users] too much TCP_MISS

On 26/10/11 19:17, benjamin fernandis wrote:
> Hi All,
>
> I setup squid on centos 6 for cache gain purpose and for that i
> configured squid.I am not having any problem while installing and
> configuring squid on Linux.
>
> But when i try to check caching is happening or not or checking
> traffic in access.log i can see too many TCP_MISS tags.
>
> Even for testing , i try to open same url for 2-3 times , but all time
> same , i can see TCP_MISS only for all requests from that site.
> -------------------------------------------------------------------------------------------
> squid.conf:
>
<snip>
> acl youtube dstdomain .youtube.com
> cache allow youtube
>

Squid default (no "cache" lines) is to cache everything it can, unless
you configure "cache deny" somehow.

You have no other "cache" lines than the one "cache allow youtube".

The way ACL lines in 3.1 and older are processed there is an implicit
policy at the end opposite to the result of the final access line.
    => Therefore the implicit default after "allow youtube" is "cache
deny all".

So "allow youtube" does nothing but create your problem. Remove and you
will get a better view of what can be cached and what has problems.

<snip>
> # We recommend you to use at least the following line.
> hierarchy_stoplist cgi-bin ?
>
> # Uncomment and adjust the following to add a disk cache directory.
> cache_dir aufs /CACHE 307200 64 512

Um, 300GB in a single cache area.

What exactly is your avg object size?

  (2^27) * N = maximum useful cache size.

>
> # Leave coredumps in the first cache dir
> coredump_dir /CACHE
>
>
>
> refresh_pattern ^ftp: 1440 20% 10080
> refresh_pattern ^gopher: 1440 0% 1440
> refresh_pattern -i \.(gif|png|jpg|jpeg|ico)$ 10080 90% 43200
> override-expire ignore-no-cache ignore-no-store ignore-private
> refresh_pattern -i \.(iso|avi|wav|mp3|mp4|mpeg|swf|flv|x-flv)$ 43200
> 90% 432000 override-expire ignore-no-cache ignore-no-store
> ignore-private
> refresh_pattern -i
> \.(deb|rpm|exe|zip|tar|tgz|ram|rar|bin|ppt|doc|tiff)$ 10080 90% 43200
> override-expire ignore-no-cache ignore-no-store ignore-private
> refresh_pattern -i \.index.(html|htm)$ 0 40% 10080
> refresh_pattern -i \.(html|htm|css|js)$ 1440 40% 40320
> refresh_pattern -i \.flv$ 10080 90% 999999 ignore-no-cache
> override-expire ignore-private
> refresh_pattern -i (/cgi-bin/|\?) 0 0% 0
> refresh_pattern . 0 40% 40320
>

ignore "private" and "no-store". really? They are very often marked
private and never to be saved to disk for good reason. Be very, very
careful with sharing private web objects to others.

.tiff for example are mostly used by online medical systems for sharing
things like x-rays and scans results. Critical systems requiring the
extremely accurate (and private) high definition images.

I suggest removing these again and completely re-assessing whether you
need any of them once you have the above change to "cache" lines fixed.

>
> cache_mem 2000 MB
> httpd_suppress_version_string on
> via off
>
> maximum_object_size_in_memory 40 KB
> maximum_object_size 4194304 KB

Go on:
   maximum_object_size 4 GB

<snip>
>
> --------------------------------------------------------------------------------------------------------------------
>
> I can only see TCP_MISS.
>
> What could be the reason ?
>
> Is there any misconfiguration or ?
>
> Please guide me to resolve this problem.
>
> squid version: 3.1.8
> centos 6 64 bit
> kernel version: 2.6.32-71.el6.x86_64
>
>
> Regards,
> Benjamin Fernandis

Amos

-- 
Please be using
   Current Stable Squid 2.7.STABLE9 or 3.1.16
   Beta testers wanted for 3.2.0.13