Re: iSCSI: Login Redirect

[Medi Montaseri <medi@montaseri.net>]

Having an upper limit imposed by the spec, limits the scalability of 
redirection as means
of load balancing. Not having a loop control mechanism is even worst.

Rajkumar Velpuri wrote:

>The Gilligan draft submitted to IPS working group in March describes
>using login re-direct for load balancing and failure recovery.
>
>The proposal in Gilligan draft was addressing issues not described in
>iSCSI draft.  I believe Lakshmi's question fits into that context.
>
>Raj Velpuri
>
>-----Original Message-----
>From: Mallikarjun C. [mailto:cbm@rose.hp.com] 
>Sent: Tuesday, July 15, 2003 10:14 AM
>To: Lakshmi Ramasubramanian; ips@ece.cmu.edu
>Subject: Re: iSCSI: Login Redirect
>
>If this mis-direction is going on to different portals within
>the same target node, I would think that it implies a serious
>configuration issue within the target node because it either
>does not have a global node-level view of the iSCSI service
>it offers, or the situation is changing too rapidly to be correct.
>
>If on the other hand, this mis-direction is forcing an 
>initiator to shuttle to different target nodes, it usually implies a
>lack of a consistent SAN-level view among the target nodes
>that are supposed to be doing cooperative redirection (which
>is what the feature was meant for).
>
>In either case, I tend to think that the issue is one of implementation/
>configuration and placing hard limits on the # of redirections in
>the spec is neither reasonable nor enforceable.   I believe that the 
>spec doesn't preclude implementations from having a limit (for ex., the 
>initiator iSCSI may decide to give up the chase after X attempts and 
>report a failure to its ULP).
>--
>Mallikarjun
>
>Mallikarjun Chadalapaka
>Networked Storage Architecture
>Network Storage Solutions
>Hewlett-Packard MS 5668 
>Roseville CA 95747
>cbm@rose.hp.com
>
>----- Original Message ----- 
>From: "Lakshmi Ramasubramanian" <nramas@windows.microsoft.com>
>To: <ips@ece.cmu.edu>
>Sent: Tuesday, July 15, 2003 8:51 AM
>Subject: iSCSI: Login Redirect
>
>
>When a target is moved (Temporary or Permanent), target
>sends an appropriate status code and gives the new target
>address. Is there a limit on the number of times a target
>can redirect login? If not, should we have one?
> 
>    Initiator logs into Portal A. 
>    Target redirects to Portal B.
>    Initiator logs into Portal B. 
>    Target now redirects to Portal C.
>    And so on...
> 
>Should we have an upper limit on the number of times a target
>can redirect the login?
> 
>thanks!
> -lakshmi
>
>  
>