Re: NFSv4 to be a default on RHEL-6

[Steve Dickson <SteveD@redhat.com>]

On 12/08/2010 09:56 AM, Ondrej Valousek wrote:
> On 08.12.2010 14:45, Ian Kent wrote:
>> On Wed, 2010-12-08 at 13:51 +0100, Ondrej Valousek wrote:
>>> On 08.12.2010 13:36, Ian Kent wrote: 
>>>> The default should be determined by mount.nfs(8) since that's what
>>>> autofs uses to perform mounts.
>>> I see, but it works only if the nfs4 root export is the same as /. It
>>> does not work otherwise. Example:
>>> Server 'dorado' exporting directory /exports which is also fsid=0 for
>>> nfs4.
>>> There is (also shared) subdirectory 'ext1' in this one. When I do:
>>>
>>> cd /net/dorado/exports/ext1
>>>
>>> ... the export is mounted using NFSv3. Theoretically if I did:
>>>
>>> cd /net/dorado/ext1
>>>
>>> ... I should have the same mounted via NFSv4, right? Unfortunately it
>>> does not work. But it should because:
>>>
>>> mount dorado:/ext1 /mnt
>>>
>>> works (giving nfs4 mount)....
>> The only information the hosts map has to go on is the export list
>> received from the server.
>>
>> There is no way for autofs to know that /exports is the global root from
>> the mountd exports information. It only knows that /exports is an export
>> and neither does it know what NFS version the server may offer for this
>> mount. That information just isn't available.
>>
>> As I said, I thought in recent Fedora releases (not sure now when this
>> should have happened), that
>>
>> mount <server>:/exports /<some mount point>
>>
>> and 
>>
>> mount <server>:/ /<some mount point>
>>
>> should both work and mount as NFSv4. Correct me if I'm wrong but your
>> point is that it is mounting as NFSv3 so perhaps we should log a bug and
>> see what the experts have to say on this.
>>
>> Ian
>>
>>
> Hi Ian,
> 
> I understand that autofs can not know that /exports is a global root. I just thought that mine:
> 
> cd /net/dorado/ext1
> 
> ... (i.e. omitting the "exports" word) should work as this way should autofs pass something like this : "mount.nfs dorado:/ext1 /net/dorado/ext1" which would succeed then, resulting in a nfs4 mount. What happens now is (obviously) that autofs can not find 'ext1' in the exports information from 'dorado' and so it fails even without trying....
It depends on your server... If your server does not support v4, the
mount will roll back to v3. An rpcinfo -p <server> will show if 
the server support v4.

steved.