[LSF/MM/BPF TOPIC] dispersed namespaces revisited

[John Meneghini]

I agree with Christoph that the current conception of dispersed namespaces fundamentally breaks the NVMe storage object model.

However, there have been several ideas proffered at FMDS to fix this and I think people are willing to make changes to TP-4034 
to redress this problem.

I think this is a topic that needs to be discussed at LSF/MM or ALPSS.

/John

On 3/23/22 13:16, Hannes Reinecke wrote:
> On 3/23/22 17:27, Christoph Hellwig wrote:
>> Hi Hannes,
>>
>> the answer is pretty simple:  dispersed namespaces are a bad idea and
>> will not be implemented in Linux, and this has been the stance since
>> this was first proposed.
>>
>> If these vendors want Linux support they can already trivially
>> implement virtual subsystems and are highly encouraged to do so.
>> (the concept of domains actually makes it even simpler than in
>> the beginning).
> 
> Guess what, that's what I have been proposing.
> And they have (somewhat) agreed.
> 
> I just wanted to use LSF to get everyone on board, and then be able to come with a proposal to NVMexpress which I know will be 
> acceptable from the Linux community.
> 
> I have a patchset ready implementing virtual subsystems based on the NS UUID (and thereby putting each namespace into a separate 
> subsystem).
> At this time it's just a PoC to demonstrate the concept; specification is not even proposed, and so it's hard to code against.
> 
> I can send a pointer to my kernel.org branch if you like.
> 
> Cheers,
> 
> Hannes