RE: I-D ACTION:draft-ietf-ips-scsi-mib-04.txt

["KRUEGER,MARJORIE (HP-Roseville,ex1)" <marjorie.krueger@hp.com>]

When I refer to a "LUN map", I mean that set of LUNs that a target will
export to a given initiator port.  There is a mapping between a particular
LUN and a target's LU.  Some target's simply have a default LUN for each LU,
and so the target conceptually only has one "LUN map".  Some targets
determine which LUN to export for an LU based on the I-T-L relationship.
That target would have multiple LUN maps.

This concept of "LUN mapping" does not accommodate a single LUN mapping to
multiple LU's - that is virtualization (or one aspect of it).  Please note:
I'm not trying to force a particular definition of "LUN mapping", I'm just
telling you what I mean when I use the term in reference to the SCSI MIB.

> -----Original Message-----
> From: Amir Shalit [mailto:amir@astutenetworks.com] 
> Sent: Wednesday, October 30, 2002 11:07 AM
> To: Mark Bakke; KRUEGER,MARJORIE (HP-Roseville,ex1)
> Cc: ips@ece.cmu.edu
> Subject: RE: I-D ACTION:draft-ietf-ips-scsi-mib-04.txt
> 
> 
> I agree on both counts. 
> 
> Its only that the expression "LUN mapping" got me confused 
> with "virtualization LUN mapping".
> 
> Amir
> 
> -----Original Message-----
> From: Mark Bakke [mailto:mbakke@cisco.com] 
> Sent: Wednesday, October 30, 2002 11:00 AM
> To: KRUEGER,MARJORIE (HP-Roseville,ex1)
> Cc: Amir Shalit; ips@ece.cmu.edu
> Subject: Re: I-D ACTION:draft-ietf-ips-scsi-mib-04.txt
> 
> 
> "KRUEGER,MARJORIE (HP-Roseville,ex1)" wrote:
> > 
> > > 1) Read/Write counters
> > >
> > > Counter32 (counting MB transferred) wrap at about 1000 hours on
> > > 10Gbps links. Can we the MIB use a Counter64 instead?
> > 
> > We want to accommodate SNMPv1 agents (which can't implement
> > Counter64), so we can add an optional counter64.  Thanks for the 
> > reminder!
> 
> Since we are back to an optional counter64, should it be in 
> bytes instead of MB?
> 
> > 
> > > 2) Virtualization
> > >
> > > An attempt was made to list all LU's which are part of a 
> LUN. In my
> > > opinion, the ultimate mechanism to represent hierarchical 
> volumes is
> 
> > > via a volume manager MIB. For the time being it will be useful to
> > > associate a {start LBA, end LBA} vector with each LU to allow for 
> > > most simplistic virtualization mapping.
> > 
> > I'm not sure what you mean.  The MIB lists all the LU's that are
> > contained within a Target device, and then a table of all the LUN 
> > mappings for those LU's.  I don't really think of "LU's 
> being part of 
> > a LUN" - the MIB doesn't try to accommodate virtualization, 
> we agree 
> > that virtualization is better represented via another MIB.  
> This MIB 
> > is an attempt to represent the simple
> > (average?) SCSI device.  Section 3.4 states that this MIB 
> is not meant
> to
> > address virtual devices, merely the "visible SCSI 
> attributes" (what a
> host
> > will see).
> 
> I agree with Marj.  Note that even target mapping (e.g. map a 
> FC target to an iSCSI target) or LUN mapping are outside the 
> scope of a SCSI MIB.
> 
> > Regards,
> > Marjorie Krueger
> > Networked Storage Architecture
> > Networked Storage Solutions
> > Hewlett-Packard
> 
> -- 
> Mark A. Bakke
> Cisco Systems
> mbakke@cisco.com
> 763.398.1054
>