RE: iSCSI Reqts: In-Order Delivery

["Douglas Otis" <dotis@sanlight.net>]

David,

iSCSI has presently made providing this impossible.  You can not make
assumptions about relative delivery rates between connections.  This can and
should be fixed.  As you know, I like my solution but there are many others.

Doug


> Doug,
>
> Attempting a fast exit ... I agree with the interpretation
> of SAM insofar as SCSI responses are concerned - the
> description of ABORT TASK in SAM (6.1) is clear that a
> SCSI response to an aborted task must not be delivered to
> an initiator after the FUNCTION COMPLETE from the ABORT
> TASK that aborted it is, and similarly for both ABORT
> TASK SET and CLEAR TASK SET.
>
> Since this requirement is contained in the
> existing requirement to adhere to SAM, we don't need
> any additional text in the iSCSI requirements draft,
> right ;-) ?
>
> ???,
> --David
>
> > -----Original Message-----
> > From:	Douglas Otis [SMTP:dotis@sanlight.net]
> > Sent:	Friday, April 20, 2001 7:50 PM
> > To:	Black_David@emc.com; ips@ece.cmu.edu
> > Subject:	RE: iSCSI Reqts: In-Order Delivery
> >
> > David,
> >
> > I suggested one solution that has several benefits.  This one suggestion
> > is
> > not the only option to resolve this issue.  Connection
> Allegiance does not
> > resolve state with respect to Management requests.  Off hand I can think
> > of
> > several other options as these requests are clearly indicated.  How this
> > problem is resolved should be considered a separate issue, but there is
> > this
> > requirement that should not be overlook.  My interpretation of
> SAM places
> > this obligation on the transport.
> >
> > Doug
> >
> >
> > > Focusing solely on the discussion needed to resolve the
> > > (last call) issue in the requirements draft:
> > >
> > > (A) Charles suggests that "ordered delivery of SCSI commands"
> > > 	should include task management commands.  That
> > > 	was the intent of the proposal and words should be
> > > 	added to make this clear.  Section 7.3 of the -06
> > > 	version of the main iSCSI document contains an
> > > 	initial version of a description of how task management
> > > 	commands can be executed immediately but have the
> > > 	effects they would have had if delivered in order.
> > >
> > > (B) Doug is concerned that the task management response
> > > 	may arrive before the responses to one or more
> > > 	commands that were affected by the task management
> > > 	command.  While his technical concern is valid,
> > > 	and has/is being discussed, I don't think foreclosing
> > > 	that discussion by requiring session-wide
> > > 	synchronization of responses in the requirements
> > > 	document is the right thing to do.  Hence I would
> > > 	not change the proposal to require such synchronization.
> > >
> > > Thanks,
> > > --David
> > >
>