Re: HIT rate first level Web cache compared to Top-level Web cac

Besides just increasing the size of the cache, you can improve the hit
rate by carefully tweaking the refresh_pattern parameters in the
squid.conf file. My primary cache (the last one in the hierarchy that I
maintain before going up to my provider's cache) maintains about a 36-45%
hit rate with about 1.6 GB of cache. I have a smaller cache that runs at
38% hit rate with only 112 MB of cached objects (!!), although that is at
a new client that has only been operational for about a week.

If you have a lot of cache space (>5 GB) AND tweak the refresh_pattern
parameters, you could probably maintain a VERY high it rate -- probably
near the theoretical max which I think is in the 50-60% range (somebody
figured it out a while ago). I have been curious for some time what would
happen if NLANR configured a root cache or two to use conf file
optimized for hit rate (i.e. with tweaked refresh_patterns). I would
expect to see the hit rate increase, but by how much I don't know. And
there is probably a reason for not playing with the refresh_patterns on
the very high level caches like those...

        -Bill kb8wyp

On Tue, 2 Sep 1997, Adam Neat wrote:

> > >
> > > When I look at the statistics of a Desire/Web-caching partner, it seems
> > > to be the way around... The HIT-rate of the "Second level cache" (the
> > > Top-level Cache) is much higher (abount 50% in March) then the HIT-rate
> > > of a First level Web caching-server (on an average32% during the same
> > > period)??
> > >
> > > can this be true or am I mistaken ??
> >
> > A couple of ideas:
> >
> > - first, note that 50% is very close to the optimal cache hit rate.
>
>
> Hello
>
> How are you able to get such high hit rates? We have 3 proxy servers running
> wiht Squid 1.1.11 and we only get between 12% and 18% hit rates!
>
> What are we doing wrong?
>
> Adam
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Received on Tue Sep 02 1997 - 08:56:30 MDT