Re: 4.1 no-pnfs mount option?

[Benny Halevy <bhalevy@panasas.com>]

On 2011-01-18 20:38, Trond Myklebust wrote:
> On Tue, 2011-01-18 at 20:35 +0200, Benny Halevy wrote: 
>> On 2011-01-18 20:28, Trond Myklebust wrote:
>>> On Tue, 2011-01-18 at 12:44 -0500, Daniel.Muntz@emc.com wrote: 
>>>>
>>>>> -----Original Message-----
>>>>> From: linux-nfs-owner@vger.kernel.org 
>>>>> [mailto:linux-nfs-owner@vger.kernel.org] On Behalf Of Trond Myklebust
>>>>> Sent: Friday, January 14, 2011 7:42 AM
>>>>> To: Jim Rees
>>>>> Cc: William A. (Andy) Adamson; linux-nfs@vger.kernel.org
>>>>> Subject: Re: 4.1 no-pnfs mount option?
>>>>>
>>>>> On Fri, 2011-01-14 at 10:38 -0500, Jim Rees wrote: 
>>>>>> William A. (Andy) Adamson wrote:
>>>>>>
>>>>>>   No mount option - just configure your machine to not load any pnfs
>>>>>>   layoutdriver modules.
>>>>>>
>>>>>> That works, thanks, but I was hoping for a way to have 
>>>>> layout and non-layout
>>>>>> mounts going on at the same time.
>>>>>
>>>>> Different VMs?
>>>>>
>>>>> Trond
>>>>
>>>> Would there be any objections to adding a "nopnfs" mount option to force this behavior?  It could be useful at least for testing, possibly for working around server problems, or if an admin knows that certain clients' usage patterns would be better served by disabling pnfs.
>>>
>>> Yes. Why should we be adding debugging mount options to the upstream
>>> code? Just test the damned pnfs code properly before it goes upstream...
>>>
>>> Trond
>>
>> Such a mount option could be useful for dealing with buggy servers (pnfs-wise) so you
>> could mount one server with pnfs and another without.
> 
> You can find ways around that. Just use 2 clients: one with pnfs
> switched on, and one with it off.
> 
> I really don't want to introduce mount options upstream unless they are
> useful in the long term. One off usefulness does not pass that test.
> 

I guess we can live with that for the short term.