Smart support

Smart support

[Daniel Stodden]

Hi everyone.

I've been browsing a bit of the kernel NVMe drivers. 

Right now I'm mainly wondering about SMART support. I got as far as
finding present scsi emulation code and the nvme-user.git repo.

What's the roadmap for nvme-scsi? Is it going to evolve into a full scsi
device translation layer? Is someone working on a smartctl driver?

Cheers,
Daniel

Smart support

[Verma, Vishal L]

> What's the roadmap for nvme-scsi? Is it going to evolve into a full scsi
> device translation layer?
> 

I wrote the SCSI emulation layer - and I don't think we currently have
any plans of extending this further (Matthew, Keith, chime in if I'm
wrong). Patches are, of course, welcome.

	-Vishal

Smart support

[Keith Busch]

On Mon, 21 Apr 2014, Verma, Vishal L wrote:
>> What's the roadmap for nvme-scsi? Is it going to evolve into a full scsi
>> device translation layer?
>
> I wrote the SCSI emulation layer - and I don't think we currently have
> any plans of extending this further (Matthew, Keith, chime in if I'm
> wrong). Patches are, of course, welcome.

Bug fixes, enhancements and updates as the translation reference changes
would be applied as anyone submits patches, but I don't know of new
features anyone is looking to get out of this layer. I only know of
tools like sg3-utils and other vendor tools being used to exercise the
driver's SCSI path and they seem to work well. Is there something missing?

Smart support

[Matthew Wilcox]

On Sat, Apr 19, 2014@04:01:11PM -0700, Daniel Stodden wrote:
> 
> Hi everyone.
> 
> I've been browsing a bit of the kernel NVMe drivers. 
> 
> Right now I'm mainly wondering about SMART support. I got as far as
> finding present scsi emulation code and the nvme-user.git repo.
> 
> What's the roadmap for nvme-scsi? Is it going to evolve into a full scsi
> device translation layer? Is someone working on a smartctl driver?

Hi Daniel,

I must confess to knowing little or nothing about what SMART requires.
If smartctl would benefit from having an NVMe-specific driver then it'd
be great if somebody worked on that.  If the nvme-scsi module needs a
couple of small enhancements to make the existing smartctl work properly,
then by all means let's add them.  You can see nvme-scsi does translate
LOG_PAGE_TEMPERATURE_PAGE and LOG_PAGE_INFORMATIONAL_EXCEPTIONS_PAGE
already, and does so by requesting the SMART page from the NVMe device.
Is there more that is needed for smartctl's purposes?

Smart support

[Daniel Stodden]

On Wed, 2014-04-23@11:35 -0400, Matthew Wilcox wrote:
> On Sat, Apr 19, 2014@04:01:11PM -0700, Daniel Stodden wrote:
> > 
> > Hi everyone.
> > 
> > I've been browsing a bit of the kernel NVMe drivers. 
> > 
> > Right now I'm mainly wondering about SMART support. I got as far as
> > finding present scsi emulation code and the nvme-user.git repo.
> > 
> > What's the roadmap for nvme-scsi? Is it going to evolve into a full scsi
> > device translation layer? Is someone working on a smartctl driver?
> 
> Hi Daniel,
> 
> I must confess to knowing little or nothing about what SMART requires.
> If smartctl would benefit from having an NVMe-specific driver then it'd
> be great if somebody worked on that.  If the nvme-scsi module needs a
> couple of small enhancements to make the existing smartctl work properly,
> then by all means let's add them.  You can see nvme-scsi does translate
> LOG_PAGE_TEMPERATURE_PAGE and LOG_PAGE_INFORMATIONAL_EXCEPTIONS_PAGE
> already, and does so by requesting the SMART page from the NVMe device.
> Is there more that is needed for smartctl's purposes?

I looked a little into it 3 days ago.

Actually I started like you said, assuming a dedicated nvme driver. Then
discovered the existing SCSI translation, so I thought solutions might
already be worked on.

Is seem that smartctl's scsi driver isn't issuing SG_IO calls, so it
fails fairly early. I'm not really good with the kernel SCSI layer, so
I'll have to look a little closer to say more.

It is as you say: if the current nvme-scsi helps keeping userland happy,
I think it's the way to go. If not, well, I guess it's a dedicated
driver then.

Might look a little further it in the near future, but don't hold your
breath yet.

Thanks everyone for the clarifications.

Daniel