LUN instantiation question

Ralph Weber ralphoweber at
Tue Mar 5 15:55:17 PST 2002

* From the T10 Reflector (t10 at, posted by:
* Ralph Weber <ralphoweber at>

> ..., what is the history of this requirement? It seems to first appear in
> SAM-2 Revision 11, July 16, 1999.

If it came in Revision 11 then I would guess that the source was:

  99-144r1 Suggested changes to REPORT LUNS command for SPC-2

> I have in mind a model where LUs are created at the behest of some client
> application with no intention that they be accessible to anyone save the
> creator. It would be of no use to notify other initiators that a new LU exists.
> So, some questions:
> 1) What is the "logical unit inventory"? Is it only the LUNs reported in
> response to REPORT LUNS? SPC-3 definition 3.1.41 seems to say this. If so,
> are LUNs that exist but are not reported by REPORT LUNS exempt from the
> unit attention requirements of 5.8.5?

It would seem so.

> 2) Could 5.8.5 be revised to provide exemption from the mandatory unit
> attention condition when a LU appears or disappears? I understand the
> importance of this behavior for some applications, but also think it's
> possible to describe a use model where such reporting is unimportant---even
> a burden.

I cannot predict how a proposal to do such would fare in CAP and T10.

It is not an editorial change and will not be made in the absence of a
T10 approved proposal.

For myself, I can say that watering down the requirement to the point
where it is meaningless would result in at least my negative vote.
Cogent justification and clear delineation of when the requirement
does and does not apply would be needed.


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