RE: iSCSI: Finding target using SendTargets Operations

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

> I have a question about the finding target information using 
> SendTargets
> Operations.
> 
> Suppose there is a FC target that can be accessed through two iSCSI-FC
> gateways (say GW1 and GW2) each having a distinct Portal Group.
> An iSCSI Initiator queries GW1 using SendTargets operation, 
> thus obtains the
> information of the target.
> This iSCSI then does the same to GW2 and finds the same target.
> 
> 1) Are both paths considered valid to the initiator? 
> or 
> 2) Path of GW2 overrides that of GW1?

If these are two gateways that are unaware of each other (no sharing of
information), they must not present the same iSCSI target name for the FC
device.  The "iSCSI-ness" of the target ends in the gateway, and iSCSI names
must be world wide unique, therefore two gateway's presenting the same
target name would be violating that rule.  Also, there's no real value in
gateway's presenting the same iSCSI name for an FC target, since initiator
SCSI layers should use LU WWN to determine that they are talking to the same
LU thru two different paths.

If a gateway doesn't share configuration information with another gateway,
it can't claim to be the same iSCSI target - the response to a "SendTarget"
request must return ALL paths to the target node name being reported (not
just the current path).  In addition, these separate gateways will have
different authorization information regarding an initiator.

Marjorie Krueger
Networked Storage Architecture
Networked Storage Solutions Org.
Hewlett-Packard