Re: 40% cache hit rates

From: David Luyer <>
Date: Thu, 24 Oct 1996 07:31:24 +0800 (WST)

On Thu, 24 Oct 1996, Martin Gleeson wrote:
>> We usually get 35-45% on requests, 40-50+% on bytes.

(these hit rates based on bytes only)

We usually get 50-60% on our 'main' cache, counting only requests from the
UWA area clients, excluding the other important internal UWA caches. If
we include the neighbors, of course, the hit rates are much higher again.

Our 'free' cache gets a 100% hit rate on bytes - it only serves data one
of the PARNet neighbours or itself already has.

Our 'small, slowed' cache [which runs bandwidth reduction software based
on a few rules for all miss requests, but is fast with neighbours and
hits] brings in about 130-160M per day and serves up 530-730M per day to
clients and neighbours - but that is a special case.

This is probably related to having a 'cache search engine' which lets
users find all the files in the PARNet area caches matching an arbitrary
string, a 'cache index' (by protocol, site then URL, a tree-like index)
and a 'top sites list' (which links to the hierachical cache index) based
on an index built at 4am each morning. The size of the PARNet area cache
is a little uncertian... one Murdoch has 8G, UWA have about 5-6G, and the
other universities... unsure :)

From the indexer - 26005 records (this is over a fixed-speed serial
                                    line for new incoming misses) - 40628 records (usually 200000+ records - something
                                    may be wrong here. still 3.25G
                                    files on disk tho. this one's new
                                    incoming is over the PARNet 4M telstra)[2] - 415 records (this does not permit new incoming
                                    misses) - 149428 records (this one runs bandwidth reduction
                                       software for new incoming over our
                                       main link, soon to be running over
                                       one of our non-telstra links) - 39377 records (this one's at Winthrop Technology, also
                                on UWA campus :) - 161947 records (Curtin University) - 266750 records (Murdoch University) - 62551 records (Edith Cowan University)

and all are running 'proxy-only' as PARNet is a 34Mbps ATM network between
campuses and all of these are very fast at connecting to each other.

Received on Wed Oct 23 1996 - 16:30:56 MDT

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