IP Storage: RE: Portal group discovery

Ken, first of all, thanks, it helps.

Let me se if I understand you correctly:

portals of the same portal group (sharing same tag) can be used

for multiple connections in session.

Portals of different portal groups can be used for multiple sessions - and

used by the initiator anyway it likes, e.g. in your example below, open two

sessions, use one actively, and if it fails, use the other one.

It does make sense,

thanks,

Dan

From: Sandars, Ken [mailto:ken_sandars@xxxxxxxxxxx]
Sent: Tuesday, October 03, 2006 6:10 PM
To: Dan Bar Dov; William Studenmund
Cc: ips@xxxxxxxx; John Hufferd; Julian Satran
Subject: RE: Portal group discovery

Example:

Router 1 SendTargets response:

    TargetName=iqn.2006-09.com.muppet:thisismytargetpleasedonthurtme

    TargetAddress=192.168.11.2:3260,1

Router 2 SendTargets response:

    TargetName=iqn.2006-09.com.muppet:thisismytargetpleasedonthurtme

    TargetAddress=192.168.12.2:3260,2

The initiator puts 2 and 2 together (ok, 1 and 2, but you see what I mean), and comes up with:

    TargetName=iqn.2006-09.com.muppet:thisismytargetpleasedonthurtme

    TargetAddress=192.168.11.2:3260,1
    TargetAddress=192.168.12.2:3260,2

So it knows three things:

(1) The name of the target

(2) That it can be reached via two portals

(3) Connections on those portals cannot be spanned into the one session

It can choose to login via either or both portals whenever it likes. There is no need for the routers to do any IP failover.

Does that help?

Ken

From: Dan Bar Dov [mailto:danb@xxxxxxxxxxxx]
Sent: Wednesday, 4 October 2006 01:43
To: William Studenmund
Cc: Sandars, Ken; ips@xxxxxxxx; John Hufferd; Julian Satran
Subject: RE: Portal group discovery

From: William Studenmund [mailto:wrstuden@xxxxxxxxxxxxxxxxx]
Sent: Tuesday, October 03, 2006 5:28 PM
To: Dan Bar Dov
Cc: Sandars, Ken; ips@xxxxxxxx; John Hufferd; Julian Satran
Subject: Re: Portal group discovery

On Oct 3, 2006, at 4:04 AM, Dan Bar Dov wrote:

It is true that you cannot run two active connections in the

same session when going through two routers.

However, is it not possible to have a single active connection,

and fail-over to a new (or a standby) connection ?

The problem is that putting both routers in the same Target Portal Group (TPG) means exactly that the initiator CAN have two active connections, in the same session, through the two portals.

So why do you want them in the same portal group? Why not just give each router a different TPG and be done with it?

If each target is in a different TPG, how do I achieve fail-over between the routers?

(other than maintaining some heart-beat between them, and moving the router IP address over).

Take care,

Bill