Knut Yrvin wrote:
Torsdag 15 juni 2006 19:38, skrev Dan Young:
15 * 128 MB = 1920 MB
1 * 256 MB = 256 MB
Sum = 2,1 GB RAM ~ 2 GB RAM (on a server with 15 thin clients)
Uh, so 4GB for the 30+ Simon asked about? 4GB is the minimum for
this, IMHO.
Yes. My mistake about the 15 clients! Yes, 4 GB is right for 30
client. But it's not a minimum. Why? The key factor is concurrent
users. Statistically there is seldom more than 60% of the clients in
use. When installing 50 thin clients no more than 30-35 of them is
concurrently in use at the most. So 4 GB is sufficient for 50 clients.
I guess it depends on how you count clients. The term is ambiguous in
terms of actual concurrent use. My experience is from classrooms where
all seats are filled constantly and come in waves. 32 kids walk in the
door, sit down, and log in within a very short period of time. This puts
tremendous strain on a server.
Think about a teacher saying "...and now open OpenOffice Writer" to a
big class.
One more recommendation; think about installing and using prelink to
speed up application launching. It's supposedly most effective on
large C++ applications (read: KDE, OpenOffice, Firefox). 30+ clients
all launching OO Writer at the same time can be interesting. ;-)
The startup time for applications on a thin client server is really
fast. It's faster than on a workstation. We have experienced that it
takes 5-6 seconds to log in and start OpenOffice.org for 30
pupils.
I'd like some of those servers. ;-) I've seen more like 5-6 minutes for
30 kids to do that on a dual 2.4GHz Xeon (somewhat memory starved at 2.5
GB of RAM) stipulating the "all at once" scenario I described.
Further, many of the advantages with prelink is merged in with gcc 3.X
and gcc 4.0.X. [edu|k]ubuntu Dapper uses GCC 4.0.3. With e.g Qt 4 and
new KDE 4.0 most of the dirty page swaping is fixed and optimised. But
that's 6-8 months ahead.
Don't know how Ubunteros feel about prelink (it's in universe); it's
installed by default on Fedora.
There are other areas that could be speeded up. In general and
simplified there four ways to do this. But when using thin client the
two first makes most effect:
1. To choose a more light weight approach, e.g change the windows
manager. Use iceWM or similar in stead of KDE or GNOME.
2. To clean up and get rid of unnecessary libraries when starting up
KDE or GNOME e.g: http://www.osnews.com/story.php?news_id=13039
Developers work on the startup times in the GNOME and KDE projects.
This improvements is on it's way.
3. Do smarter booting of the OS. Look at this presentation by
Margarita Manterola:
http://www.marga.com.ar/~marga/debian/boottime/debconf-boot.pdf
(Ubuntu has done smart things already with Dapper ...)
4. To better utilise the new features in GCC, and clean up application
code that is slow or less efficient
All good things, especially the Xfce recommendation, I'm just trying to
give practical advice about what to expect "right now". What might
happen with Edgy (and Edgy+n) is probably better served on the -devel
list. I'd rather set moderate expectations given limited information
from a prospective user, letting their expectations be exceeded should
circumstances provide.
--
Dan Young <[EMAIL PROTECTED]>
Multnomah ESD - Technology Services
503-257-1562
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