RE: iScsi:

["John Hufferd" <hufferd@us.ibm.com>]

I think you need to understand how SCSI on Shared Devices work.  If you do
not coordinate either via a Shared File System or Shared Data Base, or SCSI
Reserves, you clearly have a problem.  But this is a well known issue and
has been solved years ago with multiple SCSI Bus connections to the same
Storage Controller, and currently applies to Fiber Channel as well as
iSCSI.  Nothing new is needed in the iSCSI protocol.

.
.
.
John L. Hufferd
Senior Technical Staff Member (STSM)
IBM/SSG San Jose Ca
Main Office (408) 256-0403, Tie: 276-0403,  eFax: (408) 904-4688
Home Office (408) 997-6136, Cell: (408) 499-9702
Internet address: hufferd@us.ibm.com


Nitin Dhingra <nitin.dhingra@dcmtech.co.in>@ece.cmu.edu on 01/02/2002
09:06:50 PM

Sent by:    owner-ips@ece.cmu.edu


To:    "'Black_David@emc.com'" <Black_David@emc.com>, ips@ece.cmu.edu
cc:
Subject:    RE: iScsi:



Well, let's take a case
where you have one target and many initiators connected that target

And as iScsi is at block level, so if more than one initiator have
requested
to write at the same block address at the same time at the same target
this can create synchronization problems, don't you think?

Shouldn't you give an option like most other protocols like NFS does,
where you have a separate optional layer for locking/synchronization...

Don't you think this should be handled by iScsi??

- Nitin

 -----Original Message-----
From:       Black_David@emc.com [mailto:Black_David@emc.com]
Sent: Wednesday, January 02, 2002 3:10 PM
To:   nitin.dhingra@dcmtech.co.in; ips@ece.cmu.edu
Subject:    RE: iScsi:

I don't understand this - what exactly is broken that you think
needs to be fixed?  Many SCSI targets do implement access controls
at the logical unit level, which is in T10's domain, not iSCSI's.

--David

---------------------------------------------------
David L. Black, Senior Technologist
EMC Corporation, 42 South St., Hopkinton, MA  01748
+1 (508) 249-6449 *NEW*      FAX: +1 (508) 497-8500
black_david@emc.com         Cell: +1 (978) 394-7754
---------------------------------------------------

> -----Original Message-----
> From: Nitin Dhingra [mailto:nitin.dhingra@dcmtech.co.in]
> Sent: Wednesday, January 02, 2002 12:40 AM
> To: ips@ece.cmu.edu
> Subject: iScsi:
>
>
> Why don't you put a restriction on the read/write access to a target?
> This can solve some of the synchronization problems that can occur...
>
> And Yeah Happy New Year to All...
>
> - Nitin
>