7.10 Server freezing

[Peter]

After months of testing, I made our edubuntu thin client system live
and it froze ... twice... and I can't figure out why.

We're using Edubuntu 7.10.
We're running a dell poweredge, 2.8ghz p4 (I'm sure it's a 2.something
p4), 1gb ram,  raid 1 array of 200GB+ with 5 clients (1ghz p3, 256MB
ram).  All 10/100 network equipment.

When any of the clients boot and log in, it's fast...so nice and fast.
But after the system has been running a few hours and students begin
to use it (and I'm not there). It freezes hard. I *think* it freezes
hard b/c I haven't tested pinging it when it's down. But it doens't
reply to anything including ctrl-alt-bkspace, or ctrl-alt-f1. And I
know the /var/log/messages file stops creating --MARK--  entries
during this time. When I find it frozen, there is video, but no
response to mouse or keyboard.

In our tests, we only experimented with 1 client. Could 5 clients
create too much demand on our server? I recently installed the ssl
update and rebuilt the images...could I have done something wrong
there? And one more detail: we're posting our username-password info
per computer...it's conceivable that one user might be getting signed
in more than once. Would that do it? Or how about using Adobe Flash 9?

thx so much,
-peter
Bard High School Early College
NY, NY