Minutes for RAID working group 10/13/93 Accredited Standards Committee X3, Information Processing Systems Doc. No.: X3T9.2/93-160 R0 Date: Oct 13, 1993 Project: Ref. Doc.: Reply to: G. Penokie To: Membership of X3T9.2 From: George Penokie Subject: Minutes of RAID Study Group Meeting (10/13/93) Agenda 1. Opening Remarks 2. Attendance and Membership 3. Approval of Agenda 4. RAB Host Interface Group Activities 5. SCSI Disk Array Model (93-140r0) 6. Action Items 7. Meeting Schedule 8. Adjournment Results of Meeting 1. Opening Remarks George Penokie the RAID Study Group Chair, called the meeting to order at 9:00 am, Wednesday October 13, 1993. He thanked Everett Rigsbee of Boeing 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 X3T9.2 and would be conducted under the X3 rules. Ad hoc meetings take no final actions, but prepare recommendations for approval by the X3T9.2 task group. The voting rules for the meeting are those of the parent committee, X3T9.2. 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 11th meeting of the RAID study group. 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 X3T9.2 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 Name S Organization Electronic Mail Address ---------------------- - ------------------------- ------------------------- Mr. Doug Hagerman O Digital Equipment Corp. hagerman@starch.enet.dec. com Mr. I. Dal Allen P ENDL 2501752@mcimail.com Mr. Howard Grill O Formation Mr. David Reilly O Formation Mr. Bill Hutchison O Hewlett Packard Co. hutch@.boi.hp.com Mr. George Penokie P IBM Corp. gop@rchvmp3.vnet.ibm.com Mr. Jim McGrath P Quantum Corp. jmcgrath@qntm.com Mr Gene Milligan A Seagate Technology gene_milligan@notes.seaga te.com Mr. Robert N. Snively P Sun Microsystems, Inc bob.snively@eng.sun.com 9 people present Status Key: P - Principal A - Alternate O - Observer 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 Tarrytown, NY. Several members of the RAID Advisory Board were present. Minutes of the Tarrytown meeting were published on the SCSI Reflector. 5. RAB Host Interface Group Activities A review of the changes in Rev 0 of the SCSI Disk Array Model document (93-140r0) was made. Many changes where requested and will be incorporated into the next rev of SCSI Disk Array Model. The addressing issue was discussed extensively and an agreement was reached on the two basic issues: -the structure of the 8 byte Logic Unit Number, and -the method to use in translating the current 6 bit LUN into an 8 byte LUN. The 8 byte LUN will contain the following information for each layer of the array: -Address Mode (V-LUI or P-LUI) (2 bits) -Bus Identifier (6 bits) -Target Identifier (8 bits) This architecture only allows for SDAs to be nested four deep but no one could think for a practical implementation which would go beyond two layers deep. The translation of parallel SCSI LUNs (6 bits max) to 8 byte LUNs would be accomplished using the 6 bit LUN as a pointer into a table of 8 byte LUNs. The table would be setup using mode commands. George Penokie will write up a proposal describing this addressing. 6. SCSI Disk Array Model (93-140r0) Penokie Because this document was completely covered at the RAID Advisory Board meeting it was not discussed. The addressing ideas were discussed and there was agreement that the approach agreed to at the RAB meeting was workable. 7. Action Items 1) George Penokie will prepare revision 1 of the SCSI Disk Array Questions and Answers which includes larger LUNs and incorporates the features of Bob's proposal. 2) George Penokie will prepare a document to incorporate a new identify message into SPI to handle 8 byte LUN addresses. (93-161r0) 3) George Penokie will prepare another reversion the the SCSI Disk Array Model.(93-140-r1) 8. Meeting Schedule The next meeting of the RAID Study Group is planned for Nov 11, 1993 at the Red Lion Hotel in Colorado Springs, Co.. The meeting is expected to start at 9:00am-12:00am. This meeting will be a joint RAID Advisory Board Host Interface Group and X3T9.2 RAID Study Group meeting. George stated that starting in December the RAID Study Group meetings and the RAB Host Interface Group meetings will be held all day Tuesday on the weeks X3T9 meets. On the odd numbered months these meetings will meet in the same location as X3T9.2. On the even numbered months, if possible, these meetings will be held at the same hotel as the X3T9.3 meetings. 9. Adjournment The meeting was adjourned at 12:00 pm. on Wednesday Oct 13, 1993.