10 Configure The NFS Client

Now we install NFS on our client (192.168.0.100):

apt-get install nfs-common

Next we create the /data directory and mount our NFS share into it:

mkdir /data
mount 192.168.0.174:/data/export /data

192.168.0.174 is the virtual IP address we configured before. You must make sure that the forward and the reverse DNS record for client.example.com match each other, otherwise you get a "Permission denied" error on the client, and on the server you'll find this in /var/log/syslog:

#Mar  2 04:19:09 localhost rpc.mountd: Fake hostname localhost for 192.168.0.100 - forward lookup doesn't match reverse

If you do not have proper DNS records (or do not have a DNS server for your local network) you must change this now, otherwise you cannot mount the NFS share!

If it works you can now create further test files in /data on the client and then simulate failures of server1 and server2 (but not both at a time!) and check if the test files are replicated. On the client you shouldn't notice at all if server1 or server2 fails - the data in the /data directory should always be available (unless server1 and server2 fail at the same time...).

To unmount the /data directory, run

umount /data

If you want to automatically mount the NFS share at boot time, put the following line into /etc/fstab:

192.168.0.174:/data/export  /data    nfs          rw            0    0

Links

• NFS: http://nfs.sourceforge.net
• DRBD: http://www.drbd.org
• heartbeat / The High-Availability Linux Project: http://linux-ha.org
• The Linux Virtual Server Project: http://www.linuxvirtualserver.org