RE: [squid-users] Debugging slowness

Hi Steve,

If you are going to debug squid, you should take a look at this page:
http://wiki.squid-cache.org/KnowledgeBase/DebugSections. It describes all
the debug sections. You can specify the sections and the debug level for
each one with something like: debug_options ALL,1 85,3 88,3 22,5

Level 3 provides enough debug info without overwhelming you with unrelated
details. IMO, it's a good idea to start with the sections 85, 88 and 22 @
level 3.

Regards,
Anatoli

-----Original Message-----
From: Steve Hill [mailto:steve_at_opendium.com]
Sent: Tuesday, April 15, 2014 06:53
To: squid-users_at_squid-cache.org
Subject: [squid-users] Debugging slowness

I'm trying to debug some slowness issues with Squid 3.4.4. This is
currently under reasonably light use and every so often it becomes very
slow.

From what I can tell, the client sends a request with Negotiate auth
credentials in it. The proxy should respond with a 407 and the
negotiate challenge, but instead it sometimes just sits there for
ages... sometimes for a minute or so! (I'm not 100% convinced that this
is specific to Negotiate auth though). Squid does not appear to be
running out of file descriptors.

The problem is intermittent, which is making debugging a pain. I have a
tcpdump running and full logging turned on in squid so hopefully I can
catch some useful information the next time the problem occurs.

My question is: Once I've identified a specific request that has
experienced the problem, and want to track what Squid was doing with
that request, is there any sensible way of filtering the cache.log to
exclude the other requests that were happening concurrently?

Secondly, does anyone have any suggestions for what specific logging I
should turn on, rather than logging everything, since logging everything
slows the proxy down significantly?

Thanks.

-- 
 - Steve Hill
   Technical Director
   Opendium Limited     http://www.opendium.com
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