Re: iSCSI: naming/LUN views

[Pierre Labat <pierre_labat@hp.com>]

Mark,Jim,


Mark Bakke wrote:

> Pierre-
>
> Sorry I took so long to reply; for some reason, I didn't receive
> your original message from the reflector.
>
> I agree with all of Jim's comments, but would state this one
> more strongly:
>
>   A TargetWWUI MUST present exactly the same LU view to an
>   InitiatorWWUI regardless of the portal on which it is accessed.
>
> This means that we have a method of identification at the target
> level, which we were missing (at least as a standard) from FC and
> parallel SCSI.

Perfect.

>
>
> This was our intent, and would solve the problem you stated of
> having to compare views.  Perhaps we should add this statement
> to the document.

Yes, i think it has to be said explicitely.

Regards,

Pierre

>
>
> --
> Mark
>
> Jim Hafner wrote:
> >
> > Pierre,
> >
> > In my view, one should get the same LU view in your situation because there
> > is effectively no other information by which the target might present a
> > different view.  Namely, the target (that creates/enforces the view) is the
> > entity scoped by the TargetWWUI.  It uses the Initiator WWUI to construct
> > that LU view.  That might be constructed by rules established via SCSI
> > access controls (and yes, the InitiatorWWUI is the right mapping to
> > TransportID though that has not been formalized anywhere yet).
> >
> > This has some interesting implications.  Within the context of a single
> > SESSION established through multiple connections, there is only the one I_T
> > nexus.  But we can also establish multiple sessions between the same
> > InitiatorWWUI and TargetWWUI.  As far as access controls are concerned, the
> > views should be identical.  As for other properties of I_T nexus', e.g.,
> > reservations, the jury is still out.
> >
> > Jim Hafner
> >
> > Pierre Labat <pierre_labat@hp.com>@ece.cmu.edu on 02-27-2001 10:38:26 AM
> >
> > Sent by:  owner-ips@ece.cmu.edu
> >
> > To:   ips@ece.cmu.edu
> > cc:
> > Subject:  iSCSI: naming/LUN views
> >
> > Mark (Bakke),
> >
> > After going through the naming/discovery drafts,
> > a question came to my mind:
> >
> > Does several connections flowing through
> > several portals but using  the same initiator WWUI
> > and target WWUI will see the same thing on the target?
> > I mean by same thing: same LUs associated to the same LUNs.
> >
> > I guess that the initiator WWUI acts as an transportID (SCSI access
> > control)
> > and gives the same LUs view independently of the portal used.
> > Is it the case?
> >
> > If it is not the case, the entity that creates multiconnections
> > sessions
> > will need out of band information to know if the  2 portals can be used
> > for a same session or will have to do the  painfull job to compare the
> > LU views
> > from the two portals with no guarantee that the views could not change
> > in the future.
> >
> > Regards,
> >
> > Pierre
>
> --
> Mark A. Bakke
> Cisco Systems
> mbakke@cisco.com
> 763.398.1054