[lug] Redhat Ent5 madness again

Steve A Hart Shart at colorado.edu
Thu Mar 20 14:44:50 MDT 2008

Looks like I jumped the gun saying the problems were solved.

They appeared to be solved but have resurfaced and I'm going to start 
loosing hair out of shear frustration on this one.

Quick overview again.....

Server is running RHEnt4
Clients are running RHEnt5

all programs (firefox, thunderbird, matlab. IDL, etc) are compiled for 
RHEnt4 and are in /usr/local on the server which is then automounted on 
the clients.

Now the problem:
To rule out any type of gnome or KDE issue, I did a ctrl-alt-f6 and 
logged in that way.  So no graphical environment whatsoever.
1. start matlab with "matlab -nojvm" from within /tmp (so that 
everything is local to the system itself except matlab which is 
2. ran the following matlab script
[status,result] = system('ls')
On Hugh's setup (thanks again for testing this!) he got a time of 
0.3second which is what I was seeing before I upgraded the clients to 
RHEnt5 from Fedora Core 6.  On my current clients, it's varying from 
2-11 seconds.

If I reboot my client and try it, it will work in 0.3 second but an hour 
or so later it will go back up to 2-3 seconds or longer.

It's not an nfs issue between the client and server (i.e. automount 
related).  We monitored the network activity very closely and found that 
at no time did it show any problem.

It appears to be an issue with any type of program calling a Linux 
system command.  I say this because another user is running a shell 
script that calls /bin/sed as well as /usr/bin/g++ which is the C++ 
compiler.  This script (that on FC6 ran smoothly) is now running 
exceptionally slow on Ent5.  No matter what I do (i.e. reboot), this 
script runs like a snail.

I'm quickly running out of ideas on this and could use some more brain 
power to put this one to bed for good.

Any help/ideas would be greatly appreciated!


Steve Hart
Systems Administrator
Colorado Center for Astrodynamics Research
University of Colorado Boulder
shart at colorado.edu

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