Re: [Ips] iSCSI-specific unit attention conditions

Black_David@emc.com Sat, 04 April 2009 03:18 UTC

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Date: Fri, 3 Apr 2009 23:19:26 -0400
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Thread-Topic: [Ips] iSCSI-specific unit attention conditions
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If retirement is in order, renaming the to-be-retired codes as
vendor-specific to protect their existing usage may suffice.

I believe the original proposer of these codes will be sending
a message to this list to explain what the codes were intended
for and why.

Thanks,
--David
----------------------------------------------------
David L. Black, Distinguished Engineer
EMC Corporation, 176 South St., Hopkinton, MA  01748
+1 (508) 293-7953             FAX: +1 (508) 293-7786
black_david@emc.com        Mobile: +1 (978) 394-7754
----------------------------------------------------

> -----Original Message-----
> From: ips-bounces@ietf.org [mailto:ips-bounces@ietf.org] On 
> Behalf Of Kevin_Marks@Dell.com
> Sent: Friday, April 03, 2009 10:05 PM
> To: Frederick.Knight@netapp.com; Paul_Koning@Dell.com; 
> dcuddihy@attotech.com
> Cc: ips@ietf.org
> Subject: Re: [Ips] iSCSI-specific unit attention conditions
> 
> Fred, 
> 
> 	Whether in use or not, in my ten years of doing T10, I have
> never seen an ASC/Q go obsolete.
> 
> Kevin
> 
> 
> -----Original Message-----
> From: ips-bounces@ietf.org [mailto:ips-bounces@ietf.org] On Behalf Of
> Knight, Frederick
> Sent: Wednesday, April 01, 2009 11:23 AM
> To: Koning, Paul; dcuddihy@attotech.com
> Cc: ips@ietf.org
> Subject: Re: [Ips] iSCSI-specific unit attention conditions
> 
> I've tracked down the people involved in the original 2005 
> T10 proposal,
> and I will try to get them involved (if I can't, I'll at least share
> what I discover).
> 
> T10 will be reluctant to retire these values if they are in use. 
> 
> As mentioned, the use we see for the "ADDRESS CHANGED" event 
> is to cause
> a new discovery process to be initiated (to go find any changes).
> 
> 	Fred
> 
> -----Original Message-----
> From: Paul Koning [mailto:Paul_Koning@Dell.com] 
> Sent: Wednesday, April 01, 2009 11:51 AM
> To: dcuddihy@attotech.com
> Cc: Knight, Frederick; ips@ietf.org
> Subject: Re: [Ips] iSCSI-specific unit attention conditions
> 
> >>>>> "dcuddihy" == dcuddihy  <dcuddihy@attotech.com>; writes:
> 
>  dcuddihy> It seems to me that the more important question is how
>  dcuddihy> useful these unit attention codes are.  (For example,
>  dcuddihy> ATTO's Xtend San initiator doesn't make use of them.)  If
>  dcuddihy> initiators don't care about this information, precisely
>  dcuddihy> defining these unit attention codes (instead of depricating
>  dcuddihy> them) will be a change for the worse.
> 
> That's one of my concerns.
> 
> It seems we're just speculating what purpose these codes were intended
> to serve.  Not only don't we know for sure what that purpose was, we
> also don't know if that purpose is actually achieved.
> 
> The other concern is that these codes could be interpreted to impose a
> new requirement on targets to generate them in certain situations.  Of
> course we don't know what those situations are, or why targets should
> do this, but clearly someone could argue that those numbers exist and
> therefore are supposed to be generated.
> 
> Unless there is a solid proposal that assigns a clear meaning, and
> that meaning is valuable to initiators, I believe that the only
> correct answer is to consider what happened as a glitch in the
> standards process and remove, to the extent possible, the debris left
> behind by that glitch.
> 
> I don't see anything in the recent discussion that gets us to this
> clear meaning and useful purpose.  In particular, I see absolutely NO
> trace of "rough consensus and running code" to support the notion that
> the iSCSI standard should support these new codes.
> 
> David, can we put in motion the deprecation of these codes?
> 
>        paul
> 
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