🚀 go-pugleaf

In message <57p80g$qiu@news.ibm.net.il> - ifaa1@ibm.net.il (Yossi Cohen)
writes:
:>
:>ISPs in Europe or Asia pay, as far as I know, about $250K/Year 
:>for a T1 line to the U.S. (for the line only, not for the internet 
:>connection).
:>
:>On the other hand, traffic could have been reduced by a significant 
:>factor by using a large cache in the proxy http and ftp server. I know
:>
:>that the academic network in the UK has a cache of 6 machines with 
:>16GB each and they reach 60% hit rate.
:>
:>It is my guess that by using a huge cache, say 1TB (1000GB), it is 
:>possible to get 90% hit rate, i.e. to save 90% of the international 
:>lines cost. The cost of 1TB may be about $200k, so it seems a very 
:>good investment.
:>
:>Where am I wrong ?   
:>

Well $200K is a tad on the low side if you expect to keep the thing
spinning.  Lots of extra hardware needed to spin that much disk on a single
host.  I'ld say you would be darn lucky to do it for twice that price.

:>Does anyone know of some research done in this field of knowing 
:>how large should a cache be in order to reach 90% hit rate ?
:>

How would you measure it?  It all depends on where the users want to web
surf.  After a while the maint cost on the 1 TB drive array starts to make
the T1 link costs across the pond look pretty cheap.  Your 1 TB array is
going to eat a lot of clean power and need a lot of air conditioning too. 
All these costs have to be paid for.  Would pay many orders of magnitude for
the service?

96GB of web cache may be effective I don't think 1 TB has the same
effectiveness nor do I think you could reach 90% hit rate on a mixed set of
ISP users.  after you cache the poular sites I think folks usage would be
all over the planet.  

//=========================================//
Paul M Blais - pblais@visi.com - St Paul, MN