I have a configuration in my office, that workstations are being served with their /home/user directories by central NFS server. We have also backup server, so in case of main NFS server fails, it will be used. But this has one disadvantage, if main NFS server fails, I will have to go to every workstation, and change /etc/fstab manually to point to backup server.

And here come the question: Is it possible to configure client workstations to mount /home/user from backup machine if the main one is not responding after some time ?

The main use case would be to do this during workstation boot of course.

Thanks !

The traditional NFS resource is field#1 in /etc/fstab and the format is
server:path
According to the NFS specification from Sun Microsystems it can be a comma-separated list
server1:path1,server2:path2
or
server1,server2:path
and this is indeed intended for redundant servers.
But I have not seen this in Linux; maybe is not implemented in its NFS client.