terminals randomly disconnecting

[Gavin McCullagh]

Hi,

On Mon, 07 Jan 2008, Krsnendu dasa wrote:

> I am experiencing an unusual problem. Occasionally (every 15 mins or so) all
> the terminals just disconnect. The terminals need restarting before they
> work again.

What you say all, you mean every thin client connected to the server? 

Every 15 minutes is pretty nasty.  I guess at least it's easy enough to
repeat if you're testing.

You say the clients need restarting and I gather the server doesn't.  Can
you ping a thin client after this happens (ie without rebooting it)?  If
you press <ctrl><alt><backspace> is that enough to restart the thin client?

> In what I think may be a related issue, some times when someone is logged in
> their terminal freezes and the panel at the bottom of the screen which shows
> which windows are open just has three tabs that all say untitled window.

Have you had opportunity to watch top for a few minutes and see does some
process go wild around this point?

> Background: I am using 32 Edubuntu 7.04 on Intel Quad Core. 4 Gb RAM. I am
> using directx ldm and smbldap.

Would it be possible for you to try not using direct-x and go back to the
default ssh method?

> I am using a 100/1000 unmanaged switch which feeds 10/100 switches in each
> class.
> 
> Things I have already tried.
> At first I thought it could be the 1000 switch, so I swapped it for another
> one, but the problem remains.

Was it another similar switch?  Could it be a problem between the switches?

> Possible solutions:
> Could upgrading to Gutsy help?

It's hard to say without knowing what the cause of the problem is.

> Could it be the network card in the server?

Sounds plausible.  

> Can someone help me debug this? Are there any log files I can check to trace
> the origin of this problem?

Yes:
	/var/log/syslog
	/var/log/messages
	/var/log/kern.log
	/var/log/daemon.log

> Thanks for any help. This is really frustrating, because I had a very stable
> system with K12LTSP 6, and now with Edubutnu 7.04 I have having quite a few
> problems.

How long have you had this problem?  You've been using 7.04 for a while,
right?  Has it always happened?  Has anything changed to prompt this?

Gavin