I have just been working on couple of IBM Rational ClearCase issues where a downgrade of the nfs version from nfs 4 was needed on their RHEL machines. So, I am sharing the info about the steps to downgrade the nfs version so that it can be handy if any of you also come across the same issues.
For example, when you run showmount -e, you will find the following output for the specific mount point:
RCSRHEL6164:/ccstg on /net/RCSRHEL6164/ccstg type nfs (rw,nosuid,nodev,intr,sloppy,vers=4,addr=126.96.36.199,clientaddr=192.168.199.253)
In the above we see that the mount point is using "vers=4" which stands for nfs 4
So if you have to downgrade to nfs 3, then do the following:
On the Server:
Edit /etc/sysconfig/nfs to have following lines:
Then restart the nfs service:
# service nfs restart
This will tell rpc.mountd not to use nfs4
On the Client:
Edit /etc/nfsmount.conf configuration file and try setting:
After doing this, restart nfs and then again check the "showmount -e" command o/p it will be like this:
RCSRHEL6164:/ccstg on /net/RCSRHEL6164/ccstg type nfs (rw,nosuid,nodev,intr,sloppy,addr=188.8.131.52)
Now there is no "vers=4", which means this is not nfs 4 now.
And you have downgraded to nfs 3 version
I hope this helps any of you who are also in need of downgrading to nfs 3.
Article author: Avinash Srinivasamurthy