[PATCH 1/5] nvmet: EUI64 support

[Christoph Hellwig]

On Wed, May 09, 2018 at 09:45:29AM +0200, Hannes Reinecke wrote:
> On Wed, 9 May 2018 09:08:58 +0200
> "Christoph Hellwig" <hch at lst.de> wrote:
> 
> > On Fri, May 04, 2018 at 01:28:41PM +0200, Hannes Reinecke wrote:
> > > Allow the setting of an IEEE Extended Unique Identifier (EUI64) for
> > > each namespace. As the OUI is per subsystem ensure that the OUI
> > > part of the EUI64 value (ie the top 3 bytes) are matching for each
> > > namespace.  
> > 
> > I don't think we should support the EUI64 value.  It doesn't have
> > a lot of uniqueness, and it requires and IEEE OID to be properly
> > implemented.  Please use the UUID identifier always, unless you
> > actually doe havean IEEE OID and really want to use it, in which case
> > you should use the NGUID.
> > 
> 
> It's not so much about usability, it's about choice.
> Some users might want to set an EUI64; companies (like ours) have
> a valid OUI, so generating an EUI64 is pretty simple.
> 
> And the patch itself is pretty simple, so where's the harm?

Please always use the NGUID then.  Using a 64-bit unique
identifier is a bad idea.  And even when using NGUIDs you have to
be extremely careful to make sure they are never reused.