[K12OSN] Real Culprit

[Debbie Schiel]

Question:  Nothing but upgrading to a true dual cpu will stop the cpu usage 
from maxing out, right?  I mean, no matter how much memory I get, if the cpu 
maxes, even temporarily, it will always do that, right?

I've been gathering quotes and information for a machine that would be ideal 
for a K12ltsp server at our school in central Queensland (Australia). We 
would also only have max 30 students logging in at any one time. All the 
quotes and info I have received say DUAL.

We've ordered one now and when it's up and running I'll post the specs and 
its capabilities.

This is some advice I received from Christian Beitzel in ACT:

"...we found the formula for these boxes through much trial and error.
We started with a standard desktop box with a gig of ram and an ide hdd,
then went to a p4 server with scsi drives and 1 gig of RAM and eventually
ended up with a Dual Xeon Server with SCSI drives and 2 Gigs of RAM...
There is a formula for speccing out a
terminal server - 512 Meg Ram for the base + 50 meg per workstation. But
this is for bare minimum operation. We also experimented and found that RAM
and CPU are almost directly proportional - that is we ran a test server PIII
500 with 1 gig of ram into a few test terminals and then a PIII 1000 with
512 meg ram into the same terminals and the load results were the same."



----Original Message Follows----
From: Liam Marshall <lsrpm at mts.net>
Reply-To: "Support list for opensource software in schools." 
<k12osn at redhat.com>
To: "Support list for opensource software in schools." <k12osn at redhat.com>
Subject: [K12OSN] Real Culprit
Date: Mon, 13 Sep 2004 22:14:26 -0500

I began this thread under the subject, bottleneck Question.  I am starting a 
new thread for a variety of reasons.  Thanks to Les and others, I have 
narrowed down some of the problems, now I would like some clarification

Today I had 28 grade 7 students all log in at the exact same time, this made 
the log in process slow for everyone.  CPU usage went to 100% for a while, 
and memory usage went close to 100%  1.9GB used out of 2GB

After all got in, the cpu usage went down, but memory stayed very high.  
Then they went into oowriter, again with real slow down.  Once they were in 
and doing their individual assignments, TOP showed cpu usage of about 10-12% 
but memory stayed maxed at 1.9 out of 2

If I stagger the time for entering oowriter, ei allowing 5-6 to click on it 
at the same time, speed is acceptable, but unrealistic for teaching 
purposes.  Teachers need to give instructions and the kids need to be able 
to execute instructions near the same time.  "OK, class, everyone start 
oowriter..." or similar is a standard method, but it leads to near 
simultaneous accessing/starting of programs.

Whether it is and OpenOffice app , or Mozilla, or something as silly as 
Super Tux Racer, both cpu and memory seem to be maxing out, at least 
temporarily when programs are loading, then the cpu use usually settles 
down, (except for the games which seem to keep the cpu use maxed, but then 
again I don't care much about that, I am not teaching game play)

My long winded question is this.  Both cpu and memory max at some point.  I 
have ordered more memory, to increase memory to 4GB,  My existing 
motherboard will handle that, but it won't handle upgrading cpu

It is only a single cpu multithreading 3.06.  If I need to do that upgrade I 
need to buy a board and cpu's.

Question:  Nothing but upgrading to a true dual cpu will stop the cpu usage 
from maxing out, right?  I mean, no matter how much memory I get, if the cpu 
maxes, even temporarily, it will always do that, right?

sorry for the long winded preamble, I am just trying to get my head around 
paying the extra money


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