[K12OSN] Clients freezing, server losing network (Mathieu Pelletier)

Fri May 14 15:22:43 UTC 2010

Your network is simply saturating.  When I first set up a K12ltsp
system, we would saturate 10/100 at anything over 5 clients on a server
using anything that was graphically intense (Flash, Tux Math, etc.). The
symptoms were exactly as you described. The packets start colliding and
things go downhill quickly.

Now, at home, using an Athlon X2 and just a couple of Atom clients and
integrated intel video, I see a big difference in full screen youtube
videos going from 10/100 to gigabit . I've gone from maybe 1-2 fps to
8-10 fps. Even though it's a small network, for grins, I decided to see
if upgrading to gigabit would make a difference. I was surprised how
much a difference it made.

Moral of the story: You can't have too much bandwidth between the server
and the clients.

Regards,
William

> Message: 1
> Date: Thu, 13 May 2010 10:24:43 +0200
> From: "Mathieu Pelletier" <mpelletier at tcz.co.zw>
> To: k12osn at redhat.com
> Subject: [K12OSN] Clients freezing, server losing network
> Message-ID: <4BEBB74B.5060503 at tcz.co.zw>
> Content-Type: text/plain; charset="iso-8859-1"; Format="flowed"
> 
> Greetings Everyone,
> 
> I am having a problem with my Fedora 13 server and LTSP clients.  My 
> server is an AMD Athalon X2 Dual core, with 8 gig memory, 1 terabyte 
> striped raid array, and two ethernet cards (1 for clients, and 1 for 
> rest of the network; server is also network dhcp server).  My switches, 
> unfortunately are only 10/100 until I can upgrade them.  I am running 
> around 25 clients which all seem to run without issues.  The clients 
> (p4's with about 128mb memory) are running firefox and openoffice using 
> ltsp-localapps.  The only exception is that every now and again, the 
> clients will freeze.  On the server everything appears okay, i.e. not 
> frozen or under extreme load (the load average is somewhere around 0.42 
> or so).  However it seems like both network cards (on the server) lose 
> their connection for about ten minutes.  I cannot ping my other server 
> or any other computer for that matter.  Even if /etc/init.d/network 
> restart or ifconfig ethX down/up the cards still do not acquire a 
> network connection.  After about ten minutes the network returns and the 
> clients unfreeze.  I was wondering if maybe there is a power manager app 
> turning off the network cards on the server, but I can't seem to 
> determine if this is the cause or not.
> 
> Does anyone have any ideas on where I should start looking?  I have run 
> dmesg | grep error, etc but I cannot see anything that begins to explain 
> my problem.  Any help would be greatly appreciated.
> 
> ~Cheers!
> 
> ------------------------------------------------------------------------
> Mathieu Pelletier
> Biblical Studies Department
> Theological College of Zimbabwe
> 
> Tel: +263 9 287032/3 Ext: 214
> mpelletier at tcz.co.zw <mailto:mpelletier at tcz.co.zw>
> www.tczonline.com <http://www.tczonline.com>
> Chat Google Talk: mkpelletier Skype: mathieu.pelletier
> 
> 
> On 05/12/2010 06:00 PM, k12osn-request wrote:
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> >     1. OT: Technology Position Coos Bay Oregon (Joe Burkleo)
> >
> >
> > ----------------------------------------------------------------------
> >
> > Message: 1
> > Date: Tue, 11 May 2010 17:20:56 -0700
> > From: "Joe Burkleo"<joeb at scesd.k12.or.us>
> > To:<k12osn at redhat.com>
> > Subject: [K12OSN] OT: Technology Position Coos Bay Oregon
> > Message-ID:<4BE991F7.0F3C.0098.1 at scesd.k12.or.us>
> > Content-Type: text/plain; charset=US-ASCII
> >
> > Sorry about the off topic posting.
> >
> > We are looking for a Tech at our ESD here on the Southern Oregon Coast.
> >
> > http://www.scesd.k12.or.us/current%20job%20postings/09-10-25%20Technology%20Technician%20III.pdf
> >
> > Thanks,
> > Joe
> >
> >
> >
> >
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