[T10] Proposal 22-032r0 [Allow inquiry data to change when capacity changes] posted to T10 site

Ralph Weber Ralph.Weber at wdc.com
Thu Mar 3 16:44:36 PST 2022


The change in capacity results in a UA for MODE PARAMETERS CHANGED because the capacity is reported/managed in a parameter data header structure for MODE SENSE/SELECT commands.

The objective of 22-032 is to allow commands that most of today’s application clients expect establish a mere MODE PARAMETERS CHANGED UA to morph into commands that establish an INQUIRY DATA HAS CHANGED UA (which is an entirely different kettle of fish).

Gerry’s proposal includes the CID bit as a way for an application client to give the device server permission to establish the currently unexpected INQUIRY DATA HAS CHANGED UA. IMHO If Gerry had omitted the CID bit from 22-032r0, then CAP would have unquestionably Houlderized him into adding it.

All the best,
.Ralph

From: t10-bounces at t10.org <t10-bounces at t10.org> On Behalf Of joe at lingua-data.com
Sent: Thursday, March 3, 2022 6:29 PM
To: Frederick Knight <Frederick.Knight at netapp.com>
Cc: T10 Reflector <t10 at t10.org>
Subject: Re: [T10] Proposal 22-032r0 [Allow inquiry data to change when capacity changes] posted to T10 site

Agree that capacity may change, and that this shall result in unit attention. As but one example, I could have sworn that we collectively hashed this out in detail during the depop discussions.

Joe Breher
Manager,
lingua data, LLC
(478) 2-Breher
(478) 227-3437




On Mar 3, 2022, at 3:19 PM, Knight, Frederick <Frederick.Knight at netapp.com<mailto:Frederick.Knight at netapp.com>> wrote:

The standard already allows INQUIRY data to change any time you (the device) wants.

If INQUIRY data changes for any reason, the device server shall establish a unit attention condition for the
SCSI initiator port associated with every I_T nexus (see SAM-5), with the additional sense code set to
INQUIRY DATA HAS CHANGED.

That is pretty explicit – FOR ANY REASON – which includes when capacity is changed (or even when the moon changes phase).

                Fred


From: t10-bounces at t10.org<mailto:t10-bounces at t10.org> <t10-bounces at t10.org<mailto:t10-bounces at t10.org>> On Behalf Of Gerry Houlder
Sent: Tuesday, March 1, 2022 11:21 AM
To: T10 Reflector <t10 at t10.org<mailto:t10 at t10.org>>
Subject: Re: [T10] Proposal 22-032r0 [Allow inquiry data to change when capacity changes] posted to T10 site

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The purpose of the CID bit is to explicitly allows Inquiry data to change if the capacity is changed. The standard is silent on whether Inquiry data is allowed to change when capacity is changed but the behavior of products I am aware of is that Inquiry data is not changed when the capacity is changed. if CID=0 the customer gets current behavior (Inquiry data doesn't change) and if CID=1 then the Inuiry data is allowed to be changed.
________________________________
From: Knight, Frederick <Frederick.Knight at netapp.com<mailto:Frederick.Knight at netapp.com>>
Sent: Monday, February 28, 2022 4:14 PM
To: Gerry Houlder <gerry.houlder at seagate.com<mailto:gerry.houlder at seagate.com>>; T10 Reflector <t10 at t10.org<mailto:t10 at t10.org>>
Subject: RE: [T10] Proposal 22-032r0 [Allow inquiry data to change when capacity changes] posted to T10 site


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Why do you need the CID bit?  The UA is already spec’ed.  If the device changes the INQUIRY data, then is already is required to send the UA.  Why do you need to tell the host that you are going to OBEY the requirements the spec already has listed.

                Fred

From: t10-bounces at t10.org<mailto:t10-bounces at t10.org> <t10-bounces at t10.org<mailto:t10-bounces at t10.org>> On Behalf Of Gerry Houlder
Sent: Wednesday, February 23, 2022 9:29 PM
To: T10 Reflector <t10 at t10.org<mailto:t10 at t10.org>>
Subject: [T10] Proposal 22-032r0 [Allow inquiry data to change when capacity changes] posted to T10 site

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Proposal 22-032r0  [Allow inquiry data to change when capacity changes] is posted to T10 site. This adds a feature to SBC-5 that is similar to a feature that was approved at T13 meeting today.
https://www.t10.org/cgi-bin/ac.pl?t=d&f=22-032r0.pdf<https://secure-web.cisco.com/1mKoSEPWD7gQa02UIukXx2Amy1WyVqmjpgNAW1wxqf_a4btuVukXzHhH4IhphM6EQUmG5D1OxG71sa5uBvfV0UmsUT7CtEdnG-n5kw6OPwwyCHQEKVwlx2qHYUSzDkRq6mR_DXebR47o2wefMhr-wv-l2iqWhlyS2Mbc7TVgvDKF8wh7Rgd-zoCR318UaoCckfPw3B-deZ7WWMo86XO1aG2xmkfSJrVMEcAX4Dv9pj6w2b3NirEBiLFM8Uebf3plKNdzCBqOr-G1W1Y8kzFVSMj390W83cR5exLoEbYz-kuxHO8lApNz6C2OTmuJj31aVHKailLhNz-BRdnUcwpAVR5hD8M_-hOp9rAo7e6iVfWXI990JPoowlpplLQF50L523dyYP00vY8wjtKeGn3ttnwRgupLLwCLMSzL71urt1zciDzBag_53rPg0h8P7tL2V/https%3A%2F%2Fwww.t10.org%2Fcgi-bin%2Fac.pl%3Ft%3Dd%26f%3D22-032r0.pdf>

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