NFS Configuration

NFS is the protocol a terminal uses to mount the LTSP filesystem from the server. The terminal will then perform a pivotroot to make the remote filesystem the new root, andcontinue with the sysinit process. This process reads the configuration for the terminal from the lts.conf file and

Configuring the exports

Your LTSP server will need to be configured to export a directory or two over NFS. You will need to make sure the /etc/exports file contains entries like the following:

edit /etc/exports file

# /etc/exports: NFS file systems being exported.  See exports(5).

/var/opt/ltsp/swapfiles   192.168.0.0/255.255.255.0(rw,no_root_squash,async)
/opt/ltsp/i386            192.168.0.0/255.255.255.0(ro,no_root_squash,sync)

---

Notice that the above configuration exports two directories. The /var/opt/ltsp/swapfiles export may only be required if you wish to add some swap space to the terminals with low memory and/or local apps. The /opt/ltsp/i386 export is required for LTSP to work, and also must match the path that the option root-path line uses in your DHCP config.

Of course, if these lines don't match, the IP address is wrong in the same DHCP line, or NFS is unavailable on the server, your terminal will stop booting with a kernel panic.

Verify NFS server is running

To verify the NFS server is running on your LTSP server, use the following command:

   # showmount 192.168.0.2 -e

If the server adress is 192.168.02

You should see a couple lines like this returned:

Export list for cyclone:
/var/opt/ltsp/swapfiles 192.168.0.0/255.255.255.0
/opt/ltsp/i386      192.168.0.0/255.255.255.0

If the NFS server is not running, run the following command:

   # /etc/init.d/nfs start

Then, double check to see if the server is running, using the above showmount command. NFS uses portmapper, and can sometimes be tricky to get working. If you experience troubles, you may request help in the #ltsp channel on irc.freenode.net.

Once the NFS server is running, you are ready to move on to configuring XDMCP.

-- SteveSwitzer - 07 Dec 2004

NFS Server not responding

There's a problem that many people have had with fast server cards and slow client cards when a 2.6.x kernel is used on the server.

The message is something like:

  nfs warning: server not responding

The problem is caused by the 2.6 kernels using a large default blocksize for NFS packets. The 2.6 kernels use 32k blocks, where the older kernels used 8k blocks. What happens is the 32k byte blocks need to be broken down into 1500 byte datagrams. Simple math will tell you that you need a whole lot more 1500 byte datagrams to make up a full 32kbyte block. Sending those datagrams to a 10mbit card takes too long for all of the datagrams to get there, so the NFS client times out before getting all of the fragments.

Fortunately, there's an easy fix.

You need to pass some options to the client to tell it to use smaller block sizes for NFS.

Take a look at KernelOptions for more info passing command line args to the kernel.

Solution when using Etherboot

You'll need to add the following lines to your dhcpd.conf file.

  option option-128 code 128 = string;
  option option-129 code 129 = text;

  option option-128  e4:45:74:68:00:00;
  option option-129  "MOPTS=nolock,ro,wsize=2048,rsize=2048";

If you are wondering what the e4:45:74:68:00:00 is, read the KernelOptions page to learn about something called an "Etherboot Signature".

Solution when using PXE

Robbie had success with append NFSOPTS="-o etx"

You'll need to add the options to the pxelinux config file. By default, the config file is /tftpboot/lts/2.4.26-ltsp-3/pxelinux.cfg/default

prompt 0
label linux
  kernel bzImage-2.4.26-ltsp-3
  append init=/linuxrc rw root=/dev/ram0 initrd=initrd-2.4.26-ltsp-3.gz  MOPTS=nolock,ro,wsize=2048,rsize=2048

Different syntax in ubuntu's LTSP version

The init script in the ubuntu version of LTSP has a little different syntax: The config file is /var/lib/tftpboot/ltsp/pxelinux.cfg/default and you have to append

NFSOPTS="-o nolock,ro,wsize=2048,rsize=2048"

or

NFSOPTS="-o nolock,ro,proto=tcp"

More info on kernel args

Take a look at the following wiki article for more info on passing parameters to the kernel:

http://wiki.ltsp.org/twiki/bin/view/Ltsp/KernelOptions