On Tue, Apr 19, 2022 at 02:10:36PM +0200, Klaus Jensen wrote: > From: Klaus Jensen <k.jen...@samsung.com> > > Unconditionally set an EUI64 for namespaces. The nvme-ns device defaults > to auto-generating a persistent EUI64 if not specified, but for single > namespace setups (-device nvme,drive=...), this does not happen. > > Since the EUI64 has previously been zeroed it is not considered valid, > so it should be safe to add this now. > > The generated EUI64 is of the form 52:54:00:<namespace counter>. Note, > this is NOT the namespace identifier since that is not unique across > subsystems; it is a global namespace counter. This has the effect that > the value of this auto-generated EUI64 is dependent on the order with > which the namespaces are created. If a more flexible setup is required, > the eui64 namespace parameter should be explicitly set. Update the > documentation to make this clear.
How is this actually globally unique given that it uses a start value that is incremented for each created namespace? Also EUI64 values are based on a OUI, while NVME_EUI64_DEFAULT seems to have the OUI values cleared to all zero as far as I can tell. I would strongly advise againt autogenerating eui64 values. They are small and have little entropy, and require at least three bytes (for new allocations more) to be set to a IEEE assigned OUI.
