RAID Study Group Minutes 2/15/94

John Lohmeyer jlohmeye at ncr-mpd.FtCollinsCO.NCR.COM
Wed Mar 16 21:02:08 PST 1994

 Minutes for RAID working group 02/15/94
 Accredited Standards Committee
 X3, Information Processing Systems
                                                    Doc. No.: X3T10/94-059R0
                                                        Date: February 15,1994
                                                   Ref. Doc.:
                                                    Reply to: G. Penokie

 To:         Membership of X3T10

 From:       George Penokie and Howard Grill

 Subject:    Minutes of RAID Study Group Meeting
             February 15, 1994


 1.    Opening Remarks
 2.    Attendance and Membership
 3.    Approval of Agenda
 4.    Report on last RAID Working Group
 5.    SCSI-3 Logical Unit Addressing (94-031r1)
 6.    SDA States and Types (94-041r1)
 7.    SDA Commands and Mode Pages (94-042r1)
 8.    SCSI Disk Array Model (94-040r3)
 9.    Additional Device Models (94-025r1)
 10.   Error Handling for SCSI Controllers (94-024r1)
 11.   Action Items
 12.   Meeting Schedule
 13.   Adjournment

                               Results of Meeting

 1.  Opening Remarks

 George Penokie the RAID Study Group Chair, called the meeting to order at
 9:00 am, Tuesday, 15 February 1994.  He thanked IBM for hosting the

 As is customary, the people attending introduced themselves.  A copy of the
 attendance list was circulated for attendance and corrections.

 It was stated that the meeting had been authorized by X3T10 and would be
 conducted under the X3 rules.  Ad hoc meetings take no final actions, but
 prepare recommendations for approval by the X3T10 task group.  The voting
 rules for the meeting are those of the parent committee, X3T10.  These
 rules are:  one vote per company; and any participating company member may

 The minutes of this meeting will be posted to the SCSI BBS and the SCSI
 Reflector and will be included in the next committee mailing.

 George stated that this is the 16th meeting of the RAID study group and the
 3rd joint RAID Advisory Board/RAID study group meeting.  The purpose of the
 group is to deal with interface issues related to using RAIDs.  The study
 group will assess the issues and then formulate a strategy for dealing with

 2.  Attendance and Membership

 Attendance at working group meetings does not count toward minimum attendance
 requirements for X3T10 membership.  Working group meetings are open to any
 person or company to attend and to express their opinion on the subjects being

 The following people attended the meeting:

                      RAID Study Group Meeting Attenders

                                                       Phone Number -or-
          Name          S       Organization         Electronic Mail Address
 ---------------------- - ------------------------- -------------------------
 Mr. Keith Weber          Amphenol                  203-287-7456
 Mr. Jerry Fredin         AT&T/GIS                  316-636-8714
 Mr. M.W. Jibbe           AT&T/GIS                  316-636-8810
 Mr. Doug Hagerman        Digital Equipment Corp.   hagerman at starch.enet.
 Mr. Howard Grill         Formation                 609-234-5020
 Mr. Bill Hutchison       Hewlett Packard Co.       hutch at
 Mr. Jeffrey Williams   P Hewlett Packard Co.       jlw at
 Mr. Giles Frazier        IBM Corp.                 512-838-1802
 Mr. George Penokie       IBM Corp.                 gop at
 Mr. John Baudrexl        Intellistor Fujiitsu      303-682-6512
 Mr. David Fellinger      Mega Drive                310-247-0006
 Mr. Dick McCormick       Peer Protocols            714-476-1016
 Mr. Mike Fitzpatrick     Seagate                   405-324-3478
 Mr. Amir Majidimehr      Sony                      415-964-7426
 Mr. Tony Fung            Storage Concepts          714-852-8511
 Mr. Robert N. Snively    Sun Microsystems, Inc     bob.snively at

 15  people present

  Status Key:  P   -  Principal    ** Status not applicable at this
               A   -  Alternate       meeting because X3T10 committee
               O   -  Observer        not yet formed.
               L   -  Liaison
               S,V -  Visitor

 3.  Approval of Agenda

 The agenda developed at the meeting was approved.

 4.  Report on last RAID Working Group

 Last RAID Working Group was held in San Diego, CA.  Several members of the
 RAID Advisory Board were present.  Minutes of the Colorado Springs meeting
 were published on the SCSI Reflector.

 5.  SCSI-3 Logical Unit Addressing (94-031r1) Penokie

 George presented a revised version of the SCSI-3 Logical Unit Addressing
 proposal (X3T10/94-031r1).  Except for clarifying the SDA base address as
 zero and that this address is used for a response to the Inquiry command,
 little discussion ensued for this document.  94-031r2 will be submitted to
 the X3T10 Committee.

 6.  SDA States and Types (94-041r1) Penokie

 George presented a new document defining states of an SDA and the types of
 devices needed within Disk Arrays (X3T10/94-041r1).  Reflecting comments
 of the previous meeting, power supplies, LEDs, fans, op panel, etc. are no
 longer listed as a peripheral device type.  Whether to use a device type
 modifier or a peripheral qualifier for these is an open issue to be
 discussed at a later time.

 A significant discussion occurred on the types and reporting of SDA
 states.  The debate centered around the limitation of the SDA in
 identifying states of logical units (Volumes, Redundancy Groups) without
 first resolving its physical states.  This was in line with the notion
 that the SDA (LUN 0) is the "spokesman" for the whole unit.  To this end,
 physical SDA state types with appropriate definitions were listed as
 Readying, Available, Present, Failure, Abnormal, Addressable and
 Non-Addressable.  Logical units would continue to identify the states as
 listed in the proposal with debate to continue on how to indicate array
 state types along with the tangential issue of device type reporting to
 account for something other than a disk device type.

 7.  SDA Commands and Mode Pages (94-042r1)

 George presented a revision to the document defining the new commands and
 mode pages needed to implement SCSI disk arrays (X3T10/94-042r1).  A brief
 review was held with the major emphasis placed on noting that all these
 commands are directed at P-LUI 0 of the SDA.  It expected that this
 document will be rolled into the appropriate physical and logical services
 sections of the SDA model.

 A sidebar to the discussion was raised by Giles Frazier in his attempt to
 understand multi-level SDAs, multi-SCSI device types at each level, and
 the routing of AENs to/from the device type when the device types (e.g.
 Initiator, Target) exist under a single ID.  Resolution of the issue was
 that SDA LUN 0, knowledgeable of all addresses, will route the AEN to the
 appropriate destination.

 8.  SCSI Disk Array Model (94-040r1)

 George presented a revised version of the SCSI-3 Disk Array Model
 (X3T10/94-040r1).  Except for a few minor changes and clarifications, the
 document was accepted as described.  Discussion continued as to how to
 properly describe and control the "device types" within the SDA that do
 not have SCSI identifiers.  These are the power supplies, fans, LEDs, OP
 Panel, cache, controllers, etc.  Currently, they are included in P-LUIs;
 perhaps they should have a classifications to themselves.  If so
 classified and if given a logical unit name (e.g.  C-LUIs for component),
 then, via LUN 0 of the SDA, commands can be received that provide for
 their operation, configuration and control.  Especially attractive is the
 applicability for dual controller operation, currently being looked into
 be interested Study Group members.

 With the notion being accepted by the group, the C-LUI definition needs to
 be added to all appropriate sections of the document; similarly, where
 reference is currently made in the P-LUI, this needs to be stricken.  This
 is to be done by George for the next meeting and prior to the the document
 submission to the X3T9.10 Committee.

 9.   Additional Device Models (94-025r1)

 Doug Hagerman presented the current draft of the Additional Device Models
 (94-25r1) document.  This document proposes access mechanisms to power
 supplies, fans, and consoles.  As this was written prior to the notion of
 C-LUI as described above, it was decided to defer review until the C-LUI
 notion was documented in the SDA Model.

 A significant outgrowth of the aborted discussion was the realization
 that though a C-LUI can be associated with a Redundancy Group(s) or a
 Redundancy Group of similar C-LUIs, through, of what appears to be an
 omission, no clear way exists of identifying a C-LUI with a Redundancy
 Group.  The need to call out a C-LUI will be rectified in the next
 revision of the SDA model through the coordinated efforts of George and

 11.  Error Handling for SCSI Controllers (94-024r1)

 Doug Hagerman presented the current draft of the Error Handling for SCSI
 Controllers (94-24r1) document.  This document proposes additional error
 codes for errors encountered in RAID subsystems.  Doug has listed ASC/ASCQ
 codes for device errors, bus and general errors, subsystem command errors,
 and errors that occur during operations of the RAID device.  As the list
 is huge, a review is required to reduce the list to those not already
 covered in generic SCSI-3 and add those unique to RAID.

 12.  Action Items

  a) Penokie    Revise the SCSI-3 Addressing (94-031) document and present
                this proposal to the next plenary for a vote.
  b) Penokie    Revise the SDA States and Types (94-041) document.
  c) Penokie    Revise the SDA Commands and Mode Pages (94-042) document.
  d) Penokie    Revise the SCSI Disk Array Model (93-040) document and
                present this proposal to the next plenary for a vote.

 13.  Meeting Schedule

 The next meeting of the RAID Study Group is planned for Mar 15, 1994 at the
 Hyatt Hotel in Newport Beach, Ca.  The meeting is expected to run from
 9:00am-5:00pm.  This meeting will be a joint RAID Advisory Board Host
 Interface Group and X3T10 RAID Study Group meeting.

 14.  Adjournment

 The meeting was adjourned at 4:44 pm. on Tuesday, February 15 1994.

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