Some Advice needed on cloning a Server

[Gavin McCullagh]

Hi,

On Sat, 29 Sep 2007, jbarry wrote:

> I am currently tasked to implement and maintain a School LTSP.
> Installation went smoothly, but then when time comes to run the thing
> we have problems when students simultaneously run either of the
> following Tuxpaint, Tuxmath, childsplay and Gcompris and also the
> Client Manager gives us problems. clients will hangup and the server
> will crawl.

Several emails have appeared on this list reporting issues with these
programs.  But yet, there doesn't seem to be a single bug report either in
launchpad or the tux4kids pages.

https://launchpad.net/ubuntu/+search?text=tuxmath

First, I'd say you should try the newer versions of TuXMath, et al which
are mentioned here:

http://www.mail-archive.com/edubuntu-users@lists.ubuntu.com/msg01690.html

It's possible we can figure out the problem.  If the newer versions fix the
issue, please let us know.  If not, here are a few things to try:

1. Check /var/log/syslog on the server at the time of the crash.  See is
   there anything revealing.

2. Run the program from the command line and try to get it to crash.  See
   does any error show on the command line.

3. Look in the user's session output, /home/<username>/.xsession-errors for
   errors which look relevant (this file is a bit unwieldy sometimes as
   there are lots of warnings from various programs and there tend to be no
   time/dates).

4. Install xrestop with the package manager, start xrestop in a command
   line, run tuxmath and watch the memory usage associated with tuxmath.
   If it seems to climb without bound, that could crash the thin client, as
   several of us have recently discovered with firefox and openoffice.

5. Turn off sound on the thin client in /opt/ltsp/i386/etc/lts.conf, then
   see can you still crash it.  If not, perhaps the problem relates
   specifically to sound.

> We also have sound problems for Flash and Java games on web-pages (the
> Lab doubles as an Internet Cafe after school hours so these two are
> essential).

Do you have libflashsupport installed?

https://help.ubuntu.com/community/EdubuntuFAQ#head-9eab8b3fa984d1b72c777b67a5bb557646e5946b

If you have this, can you describe the problems you're having?

> Server: AMD Athlon X2 running Edubuntu (32 bit) 7.04
>   Dual Gigabit Nvidia Network card (unfortunately, there is a bug with
> running this card in Giga mode so I have to run it in 100mbps)
> memory: 2Gig
> Harddisk: 120 Gig SATA
> Number of Clients: 26
> Specs: AMD Sempron 2600+ with 512mb of memory.

Seems reasonable though 2GB RAM is a little short on the server for 26
clients.  100Mb/sec could also be a bit of an issue if these programs
create a lot of network activity.

> My superior is thinking of just buying harddisks for the clients so
> they become full pledge workstations, and I'm thinking that would be a
> lot of work esp. in installing and maintaining software, so advice for
> cloning workstations is also appreciated.

It should be pretty straightforward to clone Ubuntu.  Given the standard of
your thin clients they should make pretty good installed desktops too,
though there's still a lot more hassle in maintaining 26 installs, applying
security fixes, upgrading, etc. 

You can use either LDAP or NIS to give you global network logins and then
use an nfs share to share /home from the server.

> While I have read from this list a lot of discussion about LDAP I am
> afraid to try it on our production server, so as my windows upbringing
> thought me I used ghost to clone the server into an identical disk.

That won't replace ldap though, you need a way to set passwords across all
of the machines.  NIS is quite a straightforward way to do this too.

> but when I booted that disk the display would only say
> 
> GRUB
> 
> and nothing else. So maybe it cannot see the partitions since 7.04
> uses UUID in fstab, so I edited those also in the GRUB's menu.lst but
> it wont still bootup. What did I miss?
> 
> here is the partitioning scheme
> 
> /dev/sda3    as /
> /dev/sda1    as /boot
> /dev/sda4    as /home
> /dev/sda2    as swap
> 
> I need to clone the server so that I can easily try out the FAT-client
> setup and pullback to the original disk when things go bonkers.

How did you do the cloning?

Gavin