Xterminals, cpus, servers, network, bottleneck

[Philip Y. de Louraille]

I am posting this to see if some of you have already studied/encountered the
problem which I am about to post. That is, in a distributed environment: about
35 DECstations 3100 (and counting), 10 DECstations 5000 (and counting), one
DECstation 5000/200 used as a server, one DECsystem 5400, soon to be upgraded
to a 5500 system, about 10 SUN sparcs (and counting), 6-7 IBM RS6000 (and
counting), how many Xterminals can we have on the network before we will start
having difficulties with the servers and/or the network.
Let me do a bit of clarification: presently, all NCD and Tektronix Xterminals
that we have are configured from the DEC servers (5400 and 5000) and users log
in to them. So we can assume that they do all their work (Xclock, Xcalendar,
xterms, etc...., including some locally developped programs which do seismic
display, ray tracing, etc.... (meaning lots of pixmaps and cpu intensive)) on
these servers. We also have IBM Xterminals which run out of the RS6000 (two of
them are dedicated Xterms servers and it seems that they do not time share
well at all, surprise, surprise...!). At night, we have about 20 GraphOns (and
counting) and most people who have a cpu in their offices use them as GraphOn
servers, but people who have Xterminals uses the servers (DEC) for that
purpose.
More Xterminals are going to be purchased soon: probably 20 in the short time.
We probably already have 30+ of them.
When are we going to hit bottleneck?
If more details are needed before an intelligent answer can be given, by all
means, ask and I will provide.
If anything useful comes out of this posting, I will concentrate the responses
and post them.
Thank you very much!

  Philip Yzarn de Louraille                 Internet: jpyll at chevron.com
  Research Support Division                 Unix & Open Systems
  Chevron Information & Technology Co.      Tel: (213) 694-9232
  P.O. Box 446, La Habra, CA 90633-0446     Fax: (213) 694-7709
-- 
  Philip Yzarn de Louraille                 Internet: jpyll at chevron.com
  Research Support Division                 Unix & Open Systems
  Chevron Information & Technology Co.      Tel: (213) 694-9232
  P.O. Box 446, La Habra, CA 90633-0446     Fax: (213) 694-7709