RE: SCSI Format/Copy CDB support

["Amir Shalit" <amir@astutenetworks.com>]

Julo,

I was talking about initiator aborting the command
,say two hours after it was sent, and than reissue
the same command with the old CmdSN (according to
the spec).

I agree with you that the spec covers all other cases
since once a command is delivered, CmdSN doesn't
matter much and ITT or TTT are used to match the
task.

Amir

-----Original Message-----
From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
Julian Satran
Sent: Friday, January 25, 2002 2:14 PM
To: Amir Shalit
Cc: ips@ece. cmu. edu (E-mail); Julian Satran; owner-ips@ece.cmu.edu
Subject: RE: SCSI Format/Copy CDB support



Amir,
CmdSN is completely secondary in abort task.
The main element is the Initiator Task Tag.
If ITT is not found at abort then the target, under some cirscumstances,
will look for a hole at CmdSN to fill it or will answer negatively the Task
Abort.

Julo



                    "Amir Shalit"
                    <amir@astutenet       To:     Julian
Satran/Haifa/IBM@IBMIL
                    works.com>            cc:     "ips@ece. cmu. edu
\(E-mail\)" <ips@ece.cmu.edu>,
                                           <owner-ips@ece.cmu.edu>
                    25-01-02 18:49        Subject:     RE: SCSI Format/Copy
CDB support






Julo,

I agree with you on (2).

Section 2.2.2.1 is saying:
"A numbered iSCSI request will not change its allocated CmdSN
regardless of the number of times and circumstances in which it is
reissued."

A long duration SCSI command may be aborted by a task management
command and than reissued by iSCSI with a stale CmdSN.

Amir
     -----Original Message-----
     From: owner-ips@ece.cmu.edu [mailto:owner-ips@ece.cmu.edu]On Behalf Of
     Julian Satran
     Sent: Friday, January 25, 2002 1:21 AM
     To: Amir Shalit
     Cc: ips@ece. cmu. edu (E-mail); owner-ips@ece.cmu.edu
     Subject: Re: SCSI Format/Copy CDB support


     Amir,

     The draft says in several places that CmdSN is not important after the
     task gets to SCSI.
     On 2 yes you might be right but that is purely an implementation
     issue. Format commands do not time-out
     at SCSI level and iSCSI has no cause to e "nervous" - nothing is
     expected.


     Julo




   "Amir Shalit"
   <amir@astutenetworks.com>              To:        "ips@ece. cmu. edu
   Sent by: owner-ips@ece.cmu.edu \(E-mail\)" <ips@ece.cmu.edu>
                                          cc:
                                          Subject:        SCSI Format/Copy
   25-01-02 02:10                 CDB support







     I see a few problems in implementing the format/copy commands over
     iSCSI

     1) CmdSN may wrap between command and response (assuming multiple
     LUNs)

     2) iSCSI keepalive NOPs may be required to keep the connection open
     during format