Re: [storm] SPC-2 reserve/release text - version 7 (final, I hope)
"Black, David" <david.black@emc.com> Fri, 28 September 2012 23:49 UTC
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From: "Black, David" <david.black@emc.com>
To: "'cbm@chadalapaka.com'" <cbm@chadalapaka.com>, "'storm@ietf.org'" <storm@ietf.org>
Date: Fri, 28 Sep 2012 19:49:17 -0400
Thread-Topic: SPC-2 reserve/release text - version 7 (final, I hope)
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Subject: Re: [storm] SPC-2 reserve/release text - version 7 (final, I hope)
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Both changes are fine with me. Thanks, --David +++Sent from Blackberry ----- Original Message ----- From: Mallikarjun Chadalapaka [mailto:cbm@chadalapaka.com] Sent: Friday, September 28, 2012 07:23 PM To: Black, David; storm@ietf.org <storm@ietf.org> Subject: RE: SPC-2 reserve/release text - version 7 (final, I hope) Hi David, Thanks for diligently driving these text updates . Sorry, but I think we still need a couple of tweaks: Thinking more about it, I don't think iSCSI protocol spec can place a normative requirement on the overall solution outside of iSCSI. IOW, an iSCSI protocol compliance test cannot really test a "SHOULD NOT" on a SCSI feature usage (or lack thereof). So IMO, this should be a lower-case. Change: Reserve/release reservations are obsolete [SPC3] and SHOULD NOT be used To: Reserve/release reservations are obsolete [SPC3] and should not be used And one editorial (because connection failure isn't the only reason for a session failure; "target retention" can be phrased better): Change: - When connection failure causes the iSCSI session to fail, and the session is not reinstated or continued, target retention of that session's reserve/release reservation state may require an initiator to issue a reset (e.g., LOGICAL UNIT RESET, see section 11.5) in order to remove that reservation state. To: - Retention of a failed session's reserve/release reservation state by an iSCSI target, even after that failed iSCSI session is not reinstated or continued, may require an initiator to issue a reset (e.g., LOGICAL UNIT RESET, see section 11.5) in order to remove that reservation state. Thanks. Mallikarjun -----Original Message----- From: storm-bounces@ietf.org [mailto:storm-bounces@ietf.org] On Behalf Of Black, David Sent: Friday, September 28, 2012 9:48 AM To: storm@ietf.org Subject: [storm] SPC-2 reserve/release text - version 7 (final, I hope) Two more changes (UA text for session reestablishment, persistent recommendations recommendation text), and I think we're finally (!) done ... ----------------------------------------- [1] For clarity, the following change should be made in 4.4.3.1: OLD That is, it should perform session recovery as described in Chapter 6. NEW That is, it should reinstate the session via iSCSI session reinstatement (Section 6.3.5) or continue via session continuation (Section 6.3.6). END [2] Add the following sentence to the end of 4.4.3.1: Unit Attention conditions that result from session reestablishment indicate whether nexus state was preserved, see Section 6.3.4 of [SAM4]. [3] NEW TEXT: 4.4.3.2. Reservations There are two reservation management methods defined in the SCSI standards, reserve/release reservations, based on the RESERVE and RELEASE commands [SPC2], and persistent reservations, based on the PERSISTENT RESERVE IN and PERSISTENT RESERVE OUT commands [SPC3]. Reserve/release reservations are obsolete [SPC3] and SHOULD NOT be used; persistent reservations are suggested as an alternative, see Annex B of [SPC4]. State for persistent reservations is required to persist through changes and failures at the iSCSI layer that result in I_T Nexus failures, see [SPC3] for details and specific requirements. In contrast, [SPC2] does not specify detailed persistence requirements for reserve/release reservation state after an I_T Nexus failure. Nonetheless, when reserve/release reservations are supported by an iSCSI target, the preferred implementation approach is to preserve reserve/release reservation state for iSCSI session reinstatement (see Section 6.3.5) or session continuation (see Section 6.3.6). Two additional caveats apply to reserve/release reservations: - When connection failure causes the iSCSI session to fail, and the session is not reinstated or continued, target retention of that session's reserve/release reservation state may require an initiator to issue a reset (e.g., LOGICAL UNIT RESET, see section 11.5) in order to remove that reservation state. - Reserve/release reservations may not behave as expected when persistent reservations are also used on the same logical unit; see the discussion of "Exceptions to SPC-2 RESERVE and RELEASE behavior" in [SPC4]. Thanks, --David ---------------------------------------------------- David L. Black, Distinguished Engineer EMC Corporation, 176 South St., Hopkinton, MA 01748 +1 (508) 293-7953 FAX: +1 (508) 293-7786 david.black@emc.com Mobile: +1 (978) 394-7754 ---------------------------------------------------- _______________________________________________ storm mailing list storm@ietf.org https://www.ietf.org/mailman/listinfo/storm
- [storm] SPC-2 reserve/release text - version 7 (f… Black, David
- Re: [storm] SPC-2 reserve/release text - version … Mallikarjun Chadalapaka
- Re: [storm] SPC-2 reserve/release text - version … Black, David