RE: iSCSI virtualization

[Nelson Nahum <NNahum@store-age.com>]

I would like to add also my comment as our company was the first to announce
and sell an "off the data path" storage virtualization SAN appliance  (look
at http://www.store-age.com).

I think that storage virtualization is completly out of the scope of iSCSI.
One of the big advantages of storage virtualization in a SAN environment is
that allows to manage and use in a uniform way different types of storage
devices
(e.g. Protected/Unprotected, High Performance/LowCost, near/far,
FC/pSCSI/iSCSI).

For example virtualization allows a iSCSI HBA to work with a Virtual Volume
composed by FC storage and iSCSI storage.
So doing virtualization at the iSCSI level will prevent to use storage that
is not iSCSI.

It can be an issue for T10, but again, today exists very good "off the data
path" solutions without the need to the new  SCSI Status "iSCSI Reflection".

Nelson Nahum.
StoreAge Networking Technologies.


-----Original Message-----
From: John Hufferd/San Jose/IBM [mailto:hufferd@us.ibm.com]
Sent: Sunday, October 15, 2000 2:46 AM
To: ips@ece.cmu.edu
Subject: iSCSI virtualization


iSCSI Team,
With my TC Hat on:

The proposal, by Yarom, regarding virtualization has had some interesting
responses that have moved from support of the general idea to some
skepticism, to many folks wanting to delay the consideration to after the
main projects have been addressed.
Here are extracts of some of the messages (from earliest to latest and
excluding my own) :

I like the idea but am not so sure about the solution.(J.S)
I like  the basic idea of farming out the data transfer traffic to the real
devices. .... however, ...(C.M.)
I would suggest that this is an issue for T10.(J.H.)
How would discovery work in this scenario? (What would who "find"?)(D.D.)
This virtualization would make this more generally applicable,(M.B.)
The feature is very useful if it works transparently, within the framework
of existing device semantics and commands.(C.M.)
But at closer examination the case becomes weaker...(J.S.)
In my opinion,it's not [a T10 issue]. In any event, I vote for taking this
off the table.(C.M.)
I entirely agree that this is premature (Private)
I think this is an implementation issue (S.G.)
Let us keep it out of the iSCSI protocol for now. Maybe someday (S.G.)
Actually, the matter is T10 and T10 only. (R.S.)

I believe that the following is a fair statement of rough consensus:

1. The proposal, for virtualization, may have some merit.
2. We should take it off the iSCSI table (at least for now)

Therefore, based on the above, I am asking Yarom to create a Draft, which
can be fully debated, and submit it after the basic iSCSI protocol and
related projects are completed.

Hat off:

.
.
.
John L. Hufferd
Senior Technical Staff Member (STSM)
IBM/SSG San Jose Ca
(408) 256-0403, Tie: 276-0403
Internet address: hufferd@us.ibm.com