CURRENT MEETING REPORT Reported by David Wihl, Digital Equipment Corp. Minutes of the Redundant Arrays of Independent Disks BOF (RAIDMIB) The RAID MIB BOF met at the Dallas IETF on 4 December 1995. The meeting was chaired by Mark Johnson, Symbios Logic, Inc. (mark.johnson@symbios.com) Agenda: Introduction Technology - RAID and RAID mgmt History Vendor Proprietary Activities Discussion of Goals Discussion of Charter Proposal Mark provided a summary of RAID technology and RAID management technology, and its relationship to enterprise-level system management. A discussion of the general attributes of RAID management, and its complexity relative to disk management, followed. A major part of the problem statement is the development of "Network Attached" storage subsystems (whatever that ends up actually becoming) which must by definition be "network manageable." At present, network-enabled RAID management is a rather chaotic collection of vendor unique solutions. The following group of RAID vendors have developed proprietary MIB definitions to support the management of their own devices: - Symbios (NetWare only) - Adaptec - BusLogic (decided not to release?) - Storage Dimensions - Compaq - Conner - DG (Clariion) - EMC - Pacific Micro Data - AMI? By late 1994, a demand seemed to be emerging for the development of a standard for, at minimum, network monitoring of RAID and other storage-array technologies. Discussions on several Usenet newsgroups and mailing lists led to the following informal meetings being held in 1995 to discuss the possibility for agreement on a common management framework. Spring +95 N+I: Attended by technical representatives from ArrayTech, Buslogic, Conley, EMC, Hitachi, Novell, Peer, SNMP Research, Symbios, Skylight, Trimm. Discussions included presentation of two different early proposals from vendors, based on their proprietary work in existence or under development. Mid-year 95: The RAIDMIB discussion list was created, and remains available (subscription to raidmib-l-request@netx.com. Several proposals for consensus lists of management variables were discussed in the months that followed. Fall +95 N+I: BOF, Atlanta N+I. A rough draft of the charter proposal presented at the Dallas IETF was developed by consensus of those present. Attendance: Adaptec, Bell South, Conley, DEC, Fujitsu, Nabisco, RAID Advisory Board (RAB), Symbios, S/W Technologies Gr., TI. Major goals for the proposed RAIDMIB WG: - standardize basic management variables - standardize configuration description - reduce "reinvention of the wheel" - cooperate with RAID Advisory Board(RAB), an industry group of RAID providers and users, and other standards groups to develop a common language for management of array storage. Additional goals of WG: - produce a single standard MIB and MIF, with both management frameworks deriving their structure from a common, if perhaps abstract model. Overriding principle : " Enough information to fix it when it is broke." Relationships with other work in progress: Is there a dependency on the Entity MIB (containment relationship and logical dependencies)? a: Unknown at this time. If it+s present we+ll use it. Visit Entity MIB WG, Tuesday 1:00 PM. Promoters of the RAIDMIB activity need to be aware of the Entity MIB WG+s activity. We discussed the success criteria for the activity (i.e., how will a RAIDMIB WG know when to stop): - notify of fault with enough info to find the part - current status - minimal physical configuration (show inter-relationships between objects) - e.g. perhaps show S/N of drive to know that drive has moved - Provide minimal performance statistics, with as precise definitions as possible (e.g. bytes read/written, ,etc.) - where you measure it, is useful. It seems important to provide well defined information at well defined measurement points in order to make it useful across multiple vendors and products. - Provide logical mapping to physical configuration (this is where the relationship to the Entity MIB work arises). - Define something that is small, useful, and completed more quickly, rather than complete in every detail. Mechanisms already exist for vendor augmentation of a standard MIB. Technical Issues Discussion: Provisioning was raised as issue: Instrumentation should advise of potential for expansion, and notify upon new addtions. It was suggested that we should best avoid READ/CREATE row objects as opposed to READ/WRITE. q: Do we want multiple RAID subsystems per host? This could have implications for MIB naming. a: Yes, this is current state of the art. q: Both in MIB and MIF: how do we handle instrumenting two different vendors RAID subsystems on the same host? a: Unknown. To be dealt with. q: Do we want to use SCC? (The SCSI Controller Command set, the ANSI-standard model definition for storage arrays, developed principally by George Penokie of IBM) a: No, it is too complex. This conflicts with the objective of producing something small and useful, quickly. q: Do we want to use defined RAID (0, 1, 0+1, 3, 5) levels? a: Even in the RAB, RAID levels are going away (edition 6 of RAID Book). We will study this. Possibilities include: Redundant, etc. For many purposes, the RAID levels, which describe the data mapping algorithm, do not convey essential information. Knowing that redundancy exists, and which physical drives provide redundant coverage, may be more important. q: Should automated data rebuild rates be managed as a part of this discussion? If so, how? a: This was agreed to be a useful criterion. We will need to agree on a collection of "levels" of rebuild rate, based upon estimated impact to normal operations. Jeff Case suggested using a requested (r/w) value vs granted (r/o) value, to allow vendors to define their specific implementation of rebuild rates. The charter was re-visited. Cooperation with the DMTF was re- instated after deletion subsequent to the September N+I meeting. The direct references to SCSI devices were removed, in recognition of other data bus technologies. Before the meeting concluded, the following questions were asked and answered: 1. Is there sufficient interest among the providers of RAID technology in incorporating a standard MIB in their products to justify the investment in its development? 2. Is there sufficient interest among the consumers of RAID technology in deploying products incorporating a standard MIB to justify the investment in its development? 3. Is there sufficient interest among the attendees in participating in the definition of a standard MIB (i.e., are there sufficient willing workers?). The answer to all three questions was "yes." Redundant Arrays of Independent Disks "RAIDMIB" Charter Proposal Chair(s) TBD Network Management Area Director Deirdre Kostick Advisor TBD Mailing List Information raidmib-l@netx.com (to subscribe, send "subscribe raidmib-l" in the body of a message to raidmib-l-request@netx.com) Description of Working Group The RAID MIB Working Group will produce a document that defines MIB objects for use in monitoring and (possibly) controlling RAID (Redundant Arrays of Independent Disks) systems and subsystems. Three sets of managed objects are anticipated: The first set of managed objects allow the remote monitoring of RAID systems. The second set of managed objects allow the remote control of RAID systems. The third set of managed objects allow the remote configuration of RAID systems. The document resulting from the efforts of the Working Group is intended to be submitted for consideration by the IESG at the entry to the IETF standards track, i.e., as a Proposed Standard. History, Goals and Milestones: March 29 1995: First meeting at Trimm Technologies to determine interest in the concept. September 27 1995: First Interop BOF meeting in Atlanta. December, 1995: Organizational BOF at IETF, Dallas, Texas January, 1996: Working Group Chartered (?) February, 1996: Post initial draft MIB to Internet Drafts March, 1996: Working Group meetings, Los Angeles, CA May - August 1996: Additional meetings as necessary and appropriate September, 1996: Submit the RAID MIB to the IESG for consideration as a Proposed Standard. Current Internet-Drafts: None at this time. Requests for Comments: None at this time. It is the intent of this proposed Working Group to produce a standard model defining management of array devices. It is intended that this work will be done in collaboration with other bodies. Specifically, this work to define an appropriate MIB within the IETF will parallel efforts within the Desktop Management Task Force (DMTF) to define a MIF. It is intended that the MIB and MIF definitions will be closely aligned. In addition, active participation in the Working Group by designated representatives of the RAID Advisory Board will be sought and encouraged, in order to help ensure that the descriptive model that is developed reflects the desires of the RAID community as well as the network management community. Information on RAID systems The RAID Advisory Board (RAB) is the standards body that determines what is a disk array. See the book The RAIDBook for definitions of the various terms and level involved with arrays. The ISBN for the fourth edition is 1-879936-90-9. A fifth edition should be available by early in 1996. The RAIDBook is periodically updated to reflect advances in storage array technology. In addition, a storage array model is defined by ANSI X3T10 Project 1047D, the SCSI-3 Controller Command (SCC) definition. This document is an ANSI Draft Proposed Standard. No significant technical changes are anticipated prior to its approval. Revision 6 of the document, the most recent draft, may be obtained at: ftp://ftp.symbios.com/pub/standards/io/scsi3/scc-r06.ps (PostScript format). The SCC model is the basis of much of the RAB model definition.