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
Project:
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
Agenda
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
meeting.
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
vote.
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
them.
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
discussed.
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.
dec.com
Mr. Howard Grill Formation 609-234-5020
Mr. Bill Hutchison Hewlett Packard Co. hutch at .boi.hp.com
Mr. Jeffrey Williams P Hewlett Packard Co. jlw at hpdmd48.boi.hp.com
Mr. Giles Frazier IBM Corp. 512-838-1802
Mr. George Penokie IBM Corp. gop at rchvmp3.vnet.ibm.com
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 eng.sun.com
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
Doug.
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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