Re: not every song

[Matt Wakeley <matt_wakeley@agilent.com>]

Robert Reynolds wrote:

>  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.

Please read Charles Binford's message on flow control that clarifies this
issue.  To summarize, FC only prohibitted command and data IN THE SAME MESSAGE
(fc sequence).  It did not prohibit command (message/sequence) followed by
data (in a separate message/sequence).

-Matt