can you (theoretically) run only NFSv4 (without earlier versions)?

Leonid Flaks flaks at bnl.gov
Tue Dec 24 15:07:41 UTC 2013


On 12/24/2013 05:19 AM, Ed Greshko wrote:
> On 12/24/13 17:21, Tom H wrote:
>> On Tue, Dec 24, 2013 at 2:10 AM, Ed Greshko <Ed.Greshko at greshko.com> wrote:
>>> After making the suggested changes.....
>>>
>>> [root at meimei ~]# mount -o ro,nfsvers=4 192.168.0.196:/home /mnt
>>> [root at meimei ~]# mount | grep mnt
>>> 192.168.0.196:/home on /mnt type nfs4 (ro,relatime,vers=4.0,rsize=262144,wsize=262144,namlen=255,hard,proto=tcp,port=0,timeo=600,retrans=2,sec=sys,clientaddr=192.168.0.18,local_lock=none,addr=192.168.0.196)
>>> [root at meimei ~]# umount /mnt
>>>
>>> [root at meimei ~]# mount -o ro,nfsvers=3 192.168.0.196:/home /mnt
>>> mount.nfs: requested NFS version or transport protocol is not supported
>> I tried disallowing v2 and v3 on Fedora 19 and failed.
>>
>> "cat /proc/fs/nfsd/versions" shows that v2 and v3 are allowed by the
>> kernel and "mount -t -o nfsvers=3 ..." succeeds.
>>
>> I ssh'd into a RHEL 6 box and an Ubuntu 14.04 VM where I know that v2
>> and v3 are disabled.
>>
>> "cat /proc/fs/nfsd/versions" shows that v2 and v3 are disallowed and
>> "mount -t -o nfsvers=3 ..." fails.
>>
>> I must've done something wrong on Fedora 19. I'll have to try again
>> later, but I can't see anything wrong in my setup offhand.
> On an F20 system where I'm doing the testing
>
> root at f20f ~]# cat /proc/fs/nfsd/versions
> -2 -3 +4 +4.1 -4.2
>
> Shows only 4 and 4.1 allowed.
>
> I suppose I could try it on F19 for you at some point.
>
>
>
Did you look into /etc/nfsmount.conf file? It has lots of useful hints 
in comments and seems to be able to control NFS versions at 3 levels - 
per mount point, per server and globally. It is done on the client end.

Cheers,

Leon


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