Hej,
The kernel driver in /sys provide little useful information with current
releases.
Even if the nvme driver is extended in future kernels as proposed by Keith
Busch this will not solve
the problem with kernels used today.
NVMe drives are being deployed now (in mass) and it will only increase rapidly
due to the supreme performance.
I think the most important issue is to define a naming scheme in
/dev/disk/by-id to ensure consistent
naming and how to resolve this naming is secondary.
If the kernel can provide the more useful information in 4.2 it is great but we
need a scheme that is possible
to create with currently deployed kernels including 2.6.* kernels.
The scsi_id on arch 4.0.1-1 returns a ID_SERIAL of:
ID_SERIAL=SNVMe_INTEL_SSDPEDMD40CVFT504600EE400BGN
or
ID_VENDOR=NVMe
ID_MODEL=INTEL_SSDPEDMD40
ID_SCSI_SERIAL=CVFT504600EE400BGN
on the same kind of system with SuSE 12 (3.12.28) system what you would get
(different unit and serial):
ID_SERIAL=365cd2e4080864356494e000000010000
or
ID_VENDOR=NVMe
ID_MODEL=INTEL_SSDPEDMD40
ID_SCSI_SERIAL=CVFT4324006Z400BGN
A possible scheme to achieve with both is (assuming scsi_id being used):
/dev/disk/by-id/nvme-$ENV{ID_MODEL}_$ENV{ID_SCSI_SERIAL}
Distributions could then add necessary patches to achieve the same result as
long as we know what
we want to achieve.
If additional support is added in future kernel releases, systemd/udev can move
away from use of scsi_id.
BR
Per
On 14 May 2015, at 19:07 , Keith Busch <[email protected]> wrote:
> Kay Sievers <kay <at> vrfy.org> writes:
>> On Thu, May 14, 2015 at 6:12 PM, Lennart Poettering
>> <lennart <at> poettering.net> wrote:
>>> Well, nothing changed really: we'd like to remove scsi_id from
>>> systemd/udev upstream. Please ask sg_utils to pick it up
>>> instead. We'll continue to support the status quo for a while longer,
>>> but it can't stay this way, and we shouldn't add new features to
>>> it while it's in limbo.
>>
>> Yeah, not sure how much NVMe has to do with SCSI. It might make more
>> sense to export the primary values to identify these devices by the
>> kernel driver in /sys, instead of excapsulating/emulating the SCSI
>> behavior. The kernel does that for other block device types like mmc
>> too.
>
> I also like native nvme identification over scsi translation. Is the mmc
> way your preferred method for consuming these? If so, can you provide a
> pointer in that driver for what they're doing? I can probably get it in
> the nvme driver for 4.2.
>
> Thanks,
> Keith
>
> _______________________________________________
> systemd-devel mailing list
> [email protected]
> http://lists.freedesktop.org/mailman/listinfo/systemd-devel
Best Regards
Per Bergqvist
Managing Director
Bergqvist Software Technologies
Mobile: + 352 691 686 600
_______________________________________________
systemd-devel mailing list
[email protected]
http://lists.freedesktop.org/mailman/listinfo/systemd-devel
