[T10] Suspicious wording in SBC-4r16

Knight, Frederick Frederick.Knight at netapp.com
Fri Feb 1 09:27:12 PST 2019


Yes, and No.  The paragraphs are not duplicate; they do contain different information (one is about the reported capacity, and the other is about the states of the LBAs and the devices internal resources – which is different than the reported capacity).

I would suggest the following editorial change:

The device server in a thin provisioned logical unit may indicate a larger capacity in the RETURNED LOGICAL BLOCK ADDRESS field in the READ CAPACITY (10) parameter data (see 5.19.2) and the READ CAPACITY (16) parameter data (see 5.20.2) than the number of LBA mapping resources available for mapping LBAs in the logical unit.

FWIW – this is editorial because it restores the original text.  It appears that r09 intentionally removed it – but I don’t know why? R09 notes the incorporation of 15-193, 15-203, 15-218, 15-219, and an editorial change; however, none of those proposals deleted this text.

                Fred

From: t10-bounces at t10.org <t10-bounces at t10.org> On Behalf Of Gerry Houlder
Sent: Friday, January 18, 2019 4:10 PM
To: T10 Reflector <t10 at t10.org>
Subject: [T10] Suspicious wording in SBC-4r16

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Hi,
 i suspect that SBC-4 clause 4.7.3.3 is either missing some word or has an extra paragraph. This is the current wording in blue:

4.7.3.3 Thin provisioned logical unit
A thin provisioned logical unit shall support logical block provisioning management (see 4.7.3.1).

The device server in a thin provisioned logical unit may indicate a larger capacity in the RETURNED LOGICAL BLOCK ADDRESS field (see 5.19.2) and the READ CAPACITY (16) parameter data (see 5.20.2) than the number of LBA mapping resources available for mapping LBAs in the logical unit.

The device server shall map, anchor, or deallocate each LBA in a thin provisioned logical unit (see table 5). A thin provisioned logical unit is not required to provide LBA mapping resources sufficient to map all LBAs for the logical unit’s capacity as indicated in the RETURNED LOGICAL BLOCK ADDRESS field of the READ CAPACITY (10) parameter data (see 5.19.2) and the READ CAPACITY (16) parameter data (see 5.20.2).

First, the second paragraph includes READ CAPACITY (16) but does not include READ CAPACITY (10). At a bare minimum, READ CAPACITY (10) should be included in the wording next to READ CAPACITY (16) like it is in the third paragraph and like it is in clause 4.7.3.2.

Second, i observe that the third paragraph includes all of the information that is in the second paragraph plus some additional information. I suspect that in the near past the third paragraph was drafted as a replacement for the second paragraph but somehow the second paragraph was retained instead of being deleted. i would like to ask the members that have created proposals that involved these paragraphs to review the intended wording and help decide if the correct way to resolve this conundrum is to delete the second paragraph. i encourage folks with an opinion on this matter to reply to the T10 reflector before the March meeting.

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