Hierarchy/Mesh of Small Caches

From: Elfredy V. Cadapan <evc@dont-contact.us>
Date: Sun, 1 Mar 1998 19:56:48 +0800 (CST)

Hello all,

I'm currently doing a paper on the effectiveness of several small caches
(typically 30-500 Mb in size) deployed on our campus. The typical machine
configuration is Linux on low-end Intel (486 or P90-133) with less than 32
Mb RAM, IDE (not SCSI) hard disks, and either 28.8-33.6K modems or 10Mbps
Ethernet NICs. These machines also typically serve as routers,
Web servers and file servers, so I can't allocate too much hardware for
the cache.

The machines generally serve one department/institute each, and typically
have a load of less than a hundred users.

A few questions:

Has anyone else done a study on such a configuration? All the ones I've
been able to find on the Net have all been large, ISP- or country-level
caches with multigigabyte dedicated caches.

I've been browsing the ircache archives, and I saw several posts on RAIC
(redundant array of inexpensive caches). From what I've gathered, however,
it seems that this is merely a mesh of sibling caches, each storing part
of the cache (divided by .com or .edu, for example) on the same Ethernet,
and not a deployed hierarchy with lots of little caches on the end of
small, slow Internet links. (BTW, does anybody have a copyright on the
RAIC term? I'd like to know who first mentioned/invented it...)

Does anybody have a patch that makes Squid display the per-client (and
-server) bytes transmitted through cachemgr? I want to compare this to the
total traffic for each router interface (polled every 5 mins), to
determine how much Ethernet/modem traffic is actually proxy/http requests.
Not really critical, since I can always analyze the access.log and compare
it to the router logs, but having nice real-time graphs for "bytes saved
by cache" would help with getting my superiors interested in this project.
Who knows, you might even use these figures to get YOUR boss to support
your own caching efforts. :)

If anybody's interested, I've got preliminary stats on the parent cache at
http://proxy.uplb.edu.ph/mrtg/, with data on the leaf caches coming soon.

I still have about 3-4 months worth of logs to process, before I can get
any figures out, but when I do, they'll go up on that page too.

 Elfredy Cadapan
  Institute of Computer Science, Univ. of the Philippines at Los Banos
  Home page : http://www.uplb.edu.ph/~evc/
Received on Sun Mar 01 1998 - 03:57:10 MST

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