RE: Connection Consensus Progress

[Stephen Byan <Stephen.Byan@quantum.com>]

Black_David@emc.com [mailto:Black_David@emc.com] wrote:


> For a "yes" answer to (B) we need a clear grasp of the
> requirements that motivate multiple connections (i.e.,
> what problems does they address).  So far, I think
> I've seen:
> R1) Parallel transfers to/from and failover support for
> 	tape devices.  In contrast to disks, multiple SCSI
> 	connections to the same tape do not work (e.g.,
> 	blocks can be written in the wrong order).
> R2) Obtaining parallelism for a single SCSI command
> 	across multiple transport connections using
> 	different physical links.
> R3) Obtaining parallelism for a single SCSI command
> 	across multiple transport connections using the
> 	same physical links.
> R4) Optimize failure handling, so that a single TCP
> 	connection loss doesn't immediately translate
> 	into a SCSI error visible to higher level
> 	(time-consuming) recovery logic.

I think there is an additional proposed requirement, one which is satisfied
by the current iSCSI draft:

R5)	Obtaining parallelism between multiple SCSI commands
	across multiple transport connections using
	different physical links.

If I can't get R2, I'll settle for R5.

Regards,
-Steve

Steve Byan
<stephen.byan@quantum.com>
Design Engineer
MS 1-3/E23
333 South Street
Shrewsbury, MA 01545
(508)770-3414
fax: (508)770-2604