draft project proposal ("SD3") for SCSI-3 High Availability Profile
Doug, dtn 237-2145 Flames to NL: 05-Jan-1996 1408
hagerman at starch.enet.dec.com
Fri Jan 5 11:57:43 PST 1996
* From the SCSI Reflector, posted by:
* <"Doug, dtn 237-2145 Flames to NL: 05-Jan-1996 1408" <hagerman at starch.ENET.dec.com>>
The following is a text version of a draft project proposal ("SD3") for
the proposed SCSI-3 High Availability Profile technical report. Please
bring any comments on this to the working group meeting for discussion.
I hope to do a complete review of the first cut text for the technical report
at the working group meeting on Tuesday starting at about 4:00 as
noted in John's draft working group agenda. My goal is to collect ideas
on both general conceptual issues as well as specific comments on the
text of the current (clearly inadequate) draft text. I'll take any such
comments into consideration for the next draft. The current document
is number 95-314r0, distributed in a mailing and posted on the reflector
in the past.
I'll bring some copies of the project proposal and the draft text.
For a New
X3 Technical Report
SCSI High Availability Profile
December 29, 199
1. IDENTIFICATION OF PROPOSED PROJECT
1.1 TITLE: SCSI High Availability Profile (HAP).
1.2 PROPOSER: X3T10.
1.3 DATE SUBMITTED: December 29, 1995
1.4 PROJECT TYPE: DT - Development of a technical report within an X3 TC.
2. JUSTIFICATION OF PROPOSED TECHNICAL REPORT
Improvements to parallel SCSI have revealed the potential for applications of parallel SCSI to
more complex physical configurations having one or more of the following features:
a) multiple initiators connected to one bus segment
b) shared access to data stored on devices
c) devices which perform internal failover procedures on detection of device problems
d) removal and replacement of device enclosures on active buses
e) redundant components throughout the storage subsystem
2.2 RECOMMENDED SCOPE OF TECHNICAL REPORT:
Candidates for inclusion in the HAP technical report are:
a) Define an interoperability profile for parallel SCSI components
b) Identify the system-level requirements for High Availability subsystems
c) Interpret the SCC description of the use of multi-LUN devices
d) Clarify device identification procedures in the case of multiple access paths
e) Identify requirements for devices intended for use in high availability systems, including
hardware, software, microcode, and device model requirements
f) Specification of the process and procedures used to remove and replace device and host
enclosures on a SCSI bus.
g) Define requirements for Y cables, location of bus terminators, etc. as applicable to high
h) Specification of rules for non-glitch bus behavior on power cycle
i) Clarify requirements for when bus reset may be used, when bus options are renegotiated,
how to handle incoming bus resets, and the handling of message and command traffic when
a host is running its boot or console code
j) Clarify requirements for how certain data must be maintained on a per-LUN or a per-host
basis in a device
k) Clarify requirements for how hosts in a multi-host environment must coordinate the use of
mode pages, bus Ids, bus resets, and reservations
l) Clarification of the use of multiple internal controllers inside a SCSI device to provide
internal protection against device failure
2.3 EXISTING PRACTICE IN AREA OF PROPOSED TECHNICAL REPORT:
The proposed project involves the creation of a profile that standardizes the use of many optional SCSI
features. These features are currently being used in ways that are not consistent with high availability
2.4 EXPECTED STABILITY OF PROPOSED TECHNICAL REPORT WITH RESPECT TO CURRENT
AND POTENTIAL TECHNOLOGICAL ADVANCE:
The nature of the proposed project is to promote and enhance compatibility SCSI implementations from
various vendors. This should insure that current investments in SCSI are provided with more stability in
the face of technological developments..
3. DESCRIPTION OF PROPOSED PROJECT:
3.1 TYPE OF DOCUMENT: Technical Report.
3.2 DEFINITION OF CONCEPTS AND SPECIAL TERMS: None.
3.3 EXPECTED RELATIONSHIP WITH APPROVED X3 REFERENCE MODELS:
3.4 RECOMMENDED PROGRAM OF WORK:
The subject matter planned for the HAP technical report:
1) Solicit continuing participation by the current membership of X3T10 through X3 procedures.
Invite comments and proposals from organizations that may have a contribution to the HAP
2) Prepare a draft technical report based on proposals submitted and other information
gathered during the initial investigation.
3) Consider the results of HAP testing as may be available to the committee through the
voluntary efforts of the X3T10 membership.
4) Submit the draft technical report to X3 for further processing.
3.5 RESOURCES - INDIVIDUALS AND ORGANIZATIONS COMPETENT IN THE SUBJECT
The current membership of X3T10 includes representatives from all parts of the computer industry, from
semiconductor chip manufacturers to large mainframe system manufacturers as well as government
agencies. The members of X3T10 have expressed their desire to participate and cooperate in the
development of this proposed technical report.
There are sufficient resources to complete the development of this technical report without delaying work
on other projects.
3.6 RECOMMENDED X3 DEVELOPMENT TECHNICAL COMMITTEE:
It is recommended that the development work be done in Technical Committee X3T10 which is
responsible for developing the family of SCSI standards.
3.7 ANTICIPATED FREQUENCY AND DURATION OF MEETINGS:
Technical Committee X3T10 meets bimonthly. Specific task ad hoc groups are called as may be required
for one to three days between the regular meetings but their results are not binding.
3.8 TARGET DATE FOR dpANS TO X3: May 1998.
3.9 ESTIMATED USEFUL LIFE OF TECHICAL REPORT:
It is anticipated that this technical report will have a useful life of 5 years.
4. IMPLEMENTATION IMPACTS
4.1 IMPACT ON EXISTING USER PRACTICES AND INVESTMENTS:
The proposed HAP technical report will provide a definition of a standardized evolutionary growth path to
the existing practices and investments. It is likely that any isolated negative impacts would occur in any
case through non-standard evolution or revolution.
4.2 IMPACT ON SUPPLIER PRODUCTS AND SUPPORT:
4.3 TECHNIQUES AND COSTS FOR COMPLIANCE VERIFICATION:
4.4 LEGAL CONSIDERATIONS:
There are no known legal considerations. A Call for Patents will be made.
5. CLOSELY RELATED STANDARDS ACTIVITIES
5.1 EXISTING STANDARDS:
5.2 X3 STANDARDS DEVELOPMENT PROJECTS:
SCSI-3 Parallel Interface
SCSI-3 Architecture Model
SCSI-3 Interlocked Protocol
SCSI-3 Primary Commands
5.3 X3 STUDY GROUPS: None.
5.4 OTHER RELATED DOMESTIC STANDARDS EFFORTS: None.
5.5 ISO/IEC JTC 1 STANDARDS DEVELOPMENT PROJECTS: SPI, SIP, Fast-20, SAM, and SPC are
being processed as a NWI at JTC1/SC25/WG4..
5.6 OTHER RELATED INTERNATIONAL STANDARDS DEVELOPMENT PROJECTS: None.
5.7 RECOMMENDATIONS FOR COORDINATING LIAISON: None.
5.8 RECOMMENDATIONS FOR CLOSE LIAISON: None.
EPI Technical Report Project Proposal X3T10/95-213r0
More information about the T10