NFS on Debian/Ubuntu

Installation of NFS on server

Considering how powerful NFS is and the flexibility it gives you it is amazingly simple to set up. I expected it to be on a par with setting up Samba which can be a complete nightmare. Typically when setting up Samba one would use Swat or another configuration tool. With NFS set us is as easy as entering the paths you want exported into /etc/exports and making sure the correct packages are installed.

There are two implementations of NFS one runs in kernel space (nfs-kernel-server) the other in user space (nfs-user-server). The kernel space implementation is faster and more stable but if something goes wrong it could bring your box down. In reality the kernel space NFS implementation very rarely fails. I have been running it for years (and on at least one occasion for 150 days straight) and have had it fail only a couple of times. The times it did fail it simply needed restarting. In fact the only way I have even managed to get it to make a noise is when I had a box with a network card that was on the way out. The port on the card was bad which caused it to repeatedly drop and re-aquire the network sometimes several times a minute. After a few hours of that NFS would sometimes start to refuse new connections.

As well as the server you will need portmap. Fortunately if you chose NFS when you first installed the server you will have all the required packages already installed, configured and running.

One important point to remember when setting up NFS is to make sure that the user id (uid) of the user on the server matches the uid of the user on the local machine. NFS has no way of mapping "fred" on the local machine to "fred" on the server other than by relying on the uids being the same. Typically when you create a user the uid given is just the next one available but you can specify it explicitly.

Once you have made the required entries in /etc/exports you need to tell the NFS server about them. Typically I restart all three required utilities (portmap, nfs-kernel-server and nfs-common) as it is generally the best way to make sure everything is working correctly. See the section below on restarting NFS.

Step 0: Installation of NFS-server and NFS-client
Server:
# apt-get install nfs-kernel-server nfs-common portmap
Client
apt-get install nfs-common portmap

Step 1: Export directories on server
At server machine, export the directory in /etc/export file
# /etc/exports: the access control list for filesystems which may be exported
# to NFS clients. See exports(5).
/home 192.168.0.0/26(rw,sync)

Step 2: Restarting NFS on server

nfs-server:/samba#/etc/init.d/portmap start
nfs-server:/samba#/etc/init.d/nfs-kernel-server start
nfs-server:/samba#/etc/init.d/nfs-common start

Verify NFS is runnning
nfs-server:/samba# rpcinfo -p
  program vers proto   port
   100000    2   tcp    111  portmapper
   100000    2   udp    111  portmapper
   100004    2   udp    878  ypserv
   100004    1   udp    878  ypserv
   100004    2   tcp    881  ypserv
   100004    1   tcp    881  ypserv
   100009    1   udp    880  yppasswdd
600100069    1   udp    883  fypxfrd
600100069    1   tcp    885  fypxfrd
   100007    2   udp    892  ypbind
   100007    1   udp    892  ypbind
   100007    2   tcp    895  ypbind
   100007    1   tcp    895  ypbind
   100003    2   udp   2049  nfs
   100003    3   udp   2049  nfs
   100021    1   udp  32868  nlockmgr
   100021    3   udp  32868  nlockmgr
   100021    4   udp  32868  nlockmgr
   100005    1   udp    709  mountd
   100005    1   tcp    712  mountd
   100005    2   udp    709  mountd
   100005    2   tcp    712  mountd
   100005    3   udp    709  mountd
   100005    3   tcp    712  mountd
   100024    1   udp  32869  status
   100024    1   tcp  58711  status

Step3: Mounting NFS drives on Client
Add location with drive and options.

:  nfs  0 0

# Mounts from other hosts

nfs-server:/home           /home           nfs     rw,rsize=32768,wsize=32768,hard,intr,async      0       2


Mount also on command line
client:/# mount -t nfs nfs-server:/home /home

Verification of mounting the drive.
On Client verify the mount point

client:/# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1             2.8G  2.1G  578M  79% /
tmpfs                 126M     0  126M   0% /lib/init/rw
udev                   10M   52K   10M   1% /dev
tmpfs                 126M     0  126M   0% /dev/shm
nfs-server:/home         123G  105G   12G  90% /home

Reference
http://www.crazysquirrel.com/computing/debian/servers/nfs.jspx
http://www.debianhelp.co.uk/nfs.htm