Naming LUs and targets in iSCSI

Costa Sapuntzakis csapuntz at cisco.com
Tue Jun 27 19:11:08 PDT 2000


* From the T10 Reflector (t10 at t10.org), posted by:
* Costa Sapuntzakis <csapuntz at cisco.com>
*

Bob,

> The proper way to create a naming hierarchy is:
> 
> 	User selected "friendly" name, if applicable
>
> 	  pointing to:
> 
> 	     The world-wide unique identifier of the logical unit
> 
> 		   associated with:
> 
> 			a set of "initiator"||"target"||"logical unit"
> 			paths by which the logical unit can be accessed.
> 
> Hope this is some help.

This is a very clear model. Thank you.

Do you feel the friendly name or WWN should be passed in SCSI transports
or SCSI CDBs instead of the LUN?

The WWN is not enough information for an iSCSI initiator to connect to
a target logical unit. There is no server that will resolve a
WWN into a path in the global internet. Nor do I see such a server
existing because the WWN namespace is too large. Instead, iSCSI nodes will
have to be given paths along with WWNs to be able to contact a logical
unit. The URL scheme is one such technique.

The WWN can serve one of two roles when put along with a path. It
can:
         - verify the path (i.e. got to the expected LU)
         - be the last component of the path (i.e. name the LU)

As for the friendly name being different than the path. I would agree
that this would be ideal. This would require a directory service
that resolves a friendly name to WWN and path. I'm sure DNS, NDS, LDAP
could all be modified to do it and we may want to standardize
the DNS and LDAP approaches. This is  outside the scope of
the iSCSI transport but relevant to storage management.

-Costa


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