RE: [squid-users] Extremely high 'Median response time' warnings

 On lör, 2008-07-12 at 23:57 -0400, Tim Boyer wrote:
>
> > At night - times when the load should be down around zero -
> I'm seeing the
> > following response time messages:
> >
> > Jul 12 16:46:43 saratoga.denmantire.com squid[9326]: WARNING: Median
> > response time is 57448 milliseconds
>
> Could be as simple as a some automated clients running a slow
> stream of
> very slow requests (or large downloads).
>
> Daytime it goes unnoticed as there is sufficient number of interactive
> requests to make sense of the statistics, but at night when
> there is no
> interactive users these becomes very visible..
>
> > Where is this statistic coming from? I know I could
> disable it, but I'm
> > curious about why squid thinks my performance is this bad.
>
> Check your access.log at the time. I think the explanation is to be
> found there as explained above..
>
> This message exists to alert that there MAY be a problem. But
> under very
> light load statistics very easily gets scewed badly...
>
> Regards
> Henrik

Henrik -

The more I dig into this, the more I'm convinced you're correct - it's just
a measurement anomoly. I'm running sar on that box, and it's not memory,
CPU, or IO bound at those times. Nothing at all unusual in access.log, but
cache.log is firing every minute:

2008/07/12 23:35:43| WARNING: Median response time is 57448 milliseconds
2008/07/12 23:36:43| WARNING: Median response time is 57448 milliseconds
2008/07/12 23:37:43| WARNING: Median response time is 57448 milliseconds
2008/07/12 23:38:43| WARNING: Median response time is 57448 milliseconds
2008/07/12 23:39:43| WARNING: Median response time is 57448 milliseconds
2008/07/12 23:40:43| WARNING: Median response time is 57448 milliseconds
2008/07/12 23:41:43| WARNING: Median response time is 57448 milliseconds
2008/07/12 23:42:43| WARNING: Median response time is 57448 milliseconds
2008/07/12 23:43:43| WARNING: Median response time is 57448 milliseconds
2008/07/12 23:44:43| WARNING: Median response time is 57448 milliseconds
2008/07/12 23:45:43| WARNING: Median response time is 57448 milliseconds
2008/07/12 23:46:43| WARNING: Median response time is 57448 milliseconds

I think I'm just going to ignore it, especially if there aren't any users
complaining!

Thanks much,

-- tim --
Received on Tue Jul 15 2008 - 18:21:34 MDT