Re: The next step: nfsvers=4

[Steve Dickson <SteveD@redhat.com>]

Chuck Lever wrote:
> If no vers= is specified and only NFSv4 is available on the server, but
> something like "nocto" shows up on the command line mount options, do we:
> 
> a) fail the mount, or
> b) ignore the nocto option
I would say ignore this particular option... since, in a sense, v4 give you this option
by default due to delegations... but point well taken... The mapping of
v3 to v4 and visa versa will have to be addressed... I would guess in the mount
command...  
 
> 
> a) seems like the least surprising behavior.
> 
> What about "proto=udp" ?  Linux supports UDP for NFSv4, though other
> server implementations probably don't.  If that's specified on a mount
> command line without a vers= option, what version should we choose?
I think people just want things to work... so if they specify only UDP
and the server supports V4, we give them V4/TCP. If they REALLY want 
UDP, they would have to specify 'nfsvers=3,udp'.

Or, if there was an mount configuration file, they could specify the
MAX_VERSION to be 3 and then -o udp mounts work as expected...

> 
>> For implementing more complex policies, maybe we can extend
>> the command syntax to accept a range and/or an ordered list
>> of versions to try.
> 
> Steve mentioned /etc/default/nfs on Solaris.  I could see
> /etc/sysconfig/nfs on Linux containing a couple of lines defining the
> range of allowable NFS versions, if we think this is necessary.  This is
> a simple pre-existing file, and has little potential for introducing
> negative side-effects.
The /etc/sysconfig/nfs is a distro only file... Meaning I know of only 
one distro that uses that file.. So I would tend to shy away from putting
anything in that... 

steved.