RE: not every song

[Robert Reynolds <robertr@Crossroads.com>]

 I agree with Douglas.  The WRITE-DATA and DATA-RESPONSE
 message become more important when you are talking longer
 distances, and longer delays.  You can reduce your roundtrip
 latency by 1/2 on WRITE commands by using a WRITE-DATA message
 instead of independent WRITE-XFER_RDY-DATA messages.  This 
 can be a huge performance increase when talking about doing
 data replication across longer latency connections.  This is
 the difference between a 2 hour database sync. delay and a 4
 hour sync delay.

 I think it is a mistake that FCP-2 removed those messages because
 they weren't currently implemented and I think it would be
 a mistake to remove them from iSCSI.

   Bob

> -----Original Message-----
> From: Douglas Otis [mailto:dotis@sanlight.net]
> Sent: Thursday, September 28, 2000 3:50 PM
> To: Robert Snively; John Hufferd/San Jose/IBM; ips@ece.cmu.edu
> Subject: RE: not every song
> 
> 
> Bob,
> 
> I am not sure I understand the point.  Not that I would advocate such
> modifications, but should these points become a deciding 
> factor, the service
> parameter for such negotiations has already been defined 
> within FCP-2 as of
> recently.  Such a decision for removal may have been premature should
> network latency argue for Word 3, bit 3 being set.
> 
> Again, I am agnostic about this issue, but I would rather 
> stick with FCP
> structures.  Should there be attempts to provide zero copy, 
> adopting FCP
> structures permit a greater reliance on these structure's stability.
> 
> Doug
> 
> > -----Original Message-----
> > From: Robert Snively [mailto:rsnively@Brocade.COM]
> > Sent: Thursday, September 28, 2000 12:37 PM
> > To: 'Douglas Otis'; John Hufferd/San Jose/IBM; ips@ece.cmu.edu
> > Subject: RE: not every song
> >
> >
> > >  FCP
> > >  offers WRITE-DATA and READ-RESPONSE structures if desired.
> >
> > Reminder:
> >
> > No, it doesn't.  FCP-2 (the new and improved FCP) took the
> > function out because nobody implemented it and it did not make
> > sense.  It would have required additional recovery mechanisms and
> > it did not improve performance.
> >
> > Bob
> >
>