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Re: Linux Server



On Thu, 25 Mar 1999, Ury Segal wrote:


I have to concurr. These calculations are wrong. For example, using a Dual
R10000 SGI Origin 200, with 512MB memory, we accomodate 130 users, running
netscape, matlab, mathematica, and so on. The machine is indeed loaded,
but works fine.

I don't think more than a dual pII/pIII 450 (or dual Xeon 450, although I
am not sure it's really needed, price/performance wise), with 512MB and a
FAST disk, i.e. scsi UW2 >10,000rpm scsi disk is needed.

Since we here have quite a vast experience with multi user servers that
serve a large community, I think our experience is of value. I bet Doron
Shikmoni can add what he knows about BIU.


--Ariel

> 
> 
> Eli Marmor wrote:
> 
> > > Hi, Well we have been thinking along the following lines:
> > >
> > > a dual PII 350Mhz with 0.5GB RAM, 9GB diska.
> >
> > You mentioned 20 simultaneous users, each of them runs Netscape,
> > XEmacs, TeX, etc. With 0.5GB, each will have only 20MB (assuming the
> > system also eats something). I think you need more.
> 
> What can I say, If Linux can't handle 20 such users using 512M, you can
> trash it now. But, you know what? It easily can. Don't waste your money on more
> than .5 Gig.
> which is too much anyhow.
> 
> That kind of simplistic calculations is completly wrong.
> 
> 
> 
> > At least 0.75.
> > I also would prefer at least dual Xeon, or even a 4-way.
> > (I know that in the past, people could live with less, but these
> > specifications are the minimal for today's demands).
> >
> > > a) does the Linux or programs like the window manager, can run "multiple
> > > copies" economically, i.e. if one users needs sau 20MB for the core of the
> > > WM, the second user needs much less?, well i am sure that computer
> > > system experts know what i mean!!!! i cant remember the currect term to
> > > use for this.
> >
> > Of course things are shared, but only the instruction segments of the
> > executables and of the shared libraries.
> > But the critical amount of memory, at least in the examples you gave,
> > is in the data/bss. For example, a Netscape process may eat dozens of
> > megabytes after a few hours. On the other hand, you may wait a few
> > years till Netscape 5 will be ready; It is going to be very optimal
> > and will not spend resources.
> >
> > > b) How important is the internal cache of the CPU? is a PII enough.
> >
> > While the performance of the processors almost doubles itself
> > annually, it takes many years for the memory. So the cache is VERY
> > critical. The only reason why small caches are enough for most of us,
> > is because we are not 20 people on the same machine. Think how much
> > cache you would want for yourself (for single user). Now multiply it
> > by 20, and divide by the number of processors. Since we are misers,
> > divide it again by 2. This is what you need.
> >
> > Now a small tip: It is very hard to set up a so heavy machine. Offers
> > from VA Research and/or Penguin Computing may interest you, although
> > they may look expensive. Alternatively, if you find somebody else (in
> > this list?) who already has experience with these powers, order him
> > to consult you in this project. It's not a play.
> > --
> > Eli Marmor
> 
> 

   +---------------------------------------------------------------+
   | Ariel Biener                                                  |
   | e-mail: ariel@post.tau.ac.il           Work phone: 03-6406086 |
   | fingerprint = 07 D1 E5 3E EF 6D E5 82 0B E9 21 D4 3C 7D 8B BC |
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