Re: scalability of table lookup

Ed Krol (e-krol@uiuc.edu)
Tue, 8 Jun 1993 13:06:44 -0500

Date: Tue, 8 Jun 1993 13:06:44 -0500
Message-Id: <199306081806.AA23132@ux1.cso.uiuc.edu>
To: weibel@oclc.org (Stu Weibel)
From: e-krol@uiuc.edu (Ed Krol)
Subject: Re: scalability of table lookup

Stu writes:

> Is the point of UR*s to provide instantaneous access to all
> resources under all conceivable circumstances, or is it to provide a
> reliable way to identify and retrieve a resource across time in a
> changing environment (both are of obvious value)?
>
> I take it Ed's concern that (.5 sec x2) may be too slow is based on
> the requirements of Mosaic and similar systems that will try and
> service immediate demands for linked objects distributed across the
> net?

I guess I just look at the numbers of servers who might use this
facility and think it is not possible to build a centralized one
fast enough to do the job. I know this is only a guess but if we assume
that someone uses this service to move to another gopher menu every
10 seconds (every gopher server in the world handles .1 transaction/second)
then the URN resolution traffic without optimization would be around 55/sec.

If we assume the magic 8%/month growth on the Internet that means that just
gophers under those constraints would tax a 200 t/s server in a bit over 2
years.

Now consider that .1 is a paltry peek transaction rate for most gophers
(That is about what the average weekly transaction rate at the uiuc gopher
is) and that it is only one service of then net. If you add the web and
ftp and whomever else decides to use the service I think we can easily hit
200 t/s the day we turn it on.