[PATCH 8/9] nvme: implement multipath access to nvme subsystems

[Johannes Thumshirn]

[+Cc Hannes ]

Keith Busch <keith.busch at intel.com> writes:

> On Mon, Sep 25, 2017 at 03:40:30PM +0200, Christoph Hellwig wrote:
>> The new block devices nodes for multipath access will show up as
>> 
>> 	/dev/nvm-subXnZ
>
> Just thinking ahead ... Once this goes in, someone will want to boot their
> OS from a multipath target. It was a pain getting installers to recognize
> /dev/nvmeXnY as an install destination. I'm not sure if installers have
> gotten any better in the last 5 years about recognizing new block names.

We discussed (Hannes, Christoph and me) this as well offline this week
and it should eithr be possible with some udev magic (fake a
/dev/mapper/WWID symlink) or a shim device-mapper target that prevents
dm-mpath from attaching to the underlying block devices and creates a
real /dev/mapper/WWID device node (Christoph especially dislikes
this). None of them are pretty, but probably all we can do so far.

Byte,
        Johannes

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Johannes Thumshirn                                          Storage
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