Help! 10.04 LTSP configuration using only one nic

Wed Sep 7 17:33:37 UTC 2011

On Sep 7, 2011, at 10:35 AM, Jim Christiansen wrote:

> Good morning, David.  Thank you for the help and any ideas.  My clients are (year 2006) Dell GX620s with 3.6 ghz p4s and all with 1 gig ram.
Better than anything I've got!
> 
> I've never used two nics in any of my other LTSP setups as I had always kept them behind IPCOP firewalls.  I haven't had to apply iptable rules for years and really don't understand what the 1st history command, #49, is doing.  There is no mention of eth0 or what ever.

> 
> I don't know who Alkis is, but is he running his setup on a 100 megabit lan?  Could the fat image be slimmed down I wonder?
If you ever visit either irc:  #edubuntu or #ltsp during the hours of 6 AM and Midnight or beyond, Greek time, you probably have seen 'alkisg' there, and if you have asked for help either place, chances are good that he spent a good bit of time helping you.  He's both a dev and a teacher.

About the fat image being slimmed, he runs regular Ubuntu (I just asked him on the #edubuntu irc).  About the server he says:
alkisg:For fat clients, any 5 year old pc with a bit of ram + disk will do
[5:17pm]alkisg:The network speed is the greatest asset there
[5:17pm]alkisg:For thin clients, you need cpu, ram, network, etc etc
[5:18pm]
[5:20pm]alkisg:So, if he has some money to spare, tell him to go for 3 gb ram + 2 pci-e gigabit nics for the fat server.
[5:21pm]
:(for fat server)

> 
> I've just talked to the VP and he says that money is tight to purchase gig switches.  I had been thinking of yanking the 20 100 mbit switches and swapping in new gig switches.
There really needs to be at least 1, gig port, to connect the switch to the server.  alkis says of their setup:
alkisg:We use switches either with 1 or 2 gigabit ports, or full gigabit switches

> 
> I'll be in a pickle here pretty soon.  Thanks again,  Jim

Good luck!
David
> 
> On Wed, Sep 7, 2011 at 8:14 AM, David Groos <djgroos at gmail.com> wrote:
> What hardware are your fat clients running on?  Is there a difference in RAM between the good and poorly functioning clients?  I've seen these symptoms before I upgraded the RAM on all my (Pentium 4's, 2.4-2.8 GHz) fat clients to 1 gig.
> 
> Alkis insists that a regular PC (with sufficient RAM) works well as the LTSP server IF you are using fat clients.  In his labs the teachers actually uses the server as their classroom PC!  Makes the whole thing more affordable and practical.
> 
> Do you mind sharing why you chose to use a single NIC setup?  
> 
> Good luck,
> David G
> 
> On Tue, Sep 6, 2011 at 3:45 PM, Jim Christiansen <jim.c.christiansen at gmail.com> wrote:
> Hello, 
> 
> I've just had an aging server fail to start up and need to get to the bottom of another problem on another new server running Ubuntu 10.04 LTSP before attempting to do another install.  We lost one server in the Library late last June- rgreat timing and another one just today that served my classroom has failed to start up-  Both are 5 years or older.
> 
> My old Centos LTSP server for our Library died near the end of June.  My students had been playing with a new 10.04 64 setup and had it serving 32 bit fat clients, but really slowly.  One of the students altered something in iptables to make it function and I wonder if this could be the problem.  Grepping my history for iptables shows:
> 
>  49  sudo iptables --table nat --append POSTROUTING --jump MASQUERADE  --source 192.168.1.0/24
>  50  sudo sh -c 'iptables-save > /etc/ltsp/nat'
> 
> This was done, apparently, to allow the system to function with one nic.
> 
> The system is sitting on a 100 megabit network with 26 clients.  Only 1/3 to 2/3 of the clients will boot right off.  The others will linger with 4 four little streaming dots in the middle of the screen for minutes until the log in screen appears or they fail with errors:  
> 
> "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
> INFO: task modprobe:436 blocked for more than 120 seconds.
> "echo 0 >... same as 1st line
> INFO: task udev-configure-:936 blocked for more than 120 seconds.
> "echo 0 > ...same as 1st line
> INO: taskhdparm:1020 blocked for more than 120 seconds.
> "echo 0 > ...same as 1st line
> INFO: task S32ltsp-client-:1027 blocked for more than 120 seconds.
> 
> It doesn't seem any better it I boot fewer clients or more... They just don't all start up reliably.
> 
> The clients run awesomely once students get logged on.
> 
> Does anyone know what the problem could be?  I'm wondering if the natting is the problem or if I have other issues.
> 
> Thanks everyone,
> 
> Jim
> 
> 
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