Re: Connection Recovery

["Rahul Bhagwat" <rahulb@veritas.com>]

Hi,


The only possible state that CLEANUP_WAIT eventually ends up is
FREE (on timeout or successful implicit/explicit logout).

If task reassignment happens unrelated to connection state, is there any
other resource associated with connection that can be still used while it is
in CLEANUP_WAIT state.

Why do we have to wait for initiator to send logout to clean up things.

Regards,
Rahul
>
> A successful connection logout (implicit or explicit) must precede the
> task reassignments during a connection recovery operation.
>
> But please note that the notion of "connection cleanup" (graceful closing
of
> a
> previously operational iSCSI connection) in the state diagrams goes beyond
> the connection recovery (in fact, that is the reason I renamed from its
> previous
> name, please refer to my email to ips on 11/2/01 with the slide posting
> announcement).
> A connection cleanup is highly desirable even in the absence of task
> reassignment,
> to quickly reclaim the tags and buffers on either end (or, both sides
would
> have
> to wait for a connection timeout to happen, symbolized by the M1
> transition).
>
> >Once a CSM-E or a CSM-I
> >drives the connection to free state, all the pending tasks need to be
freed
> up.
>
> Not correct.  The decision to free up the pending tasks is depedent on the
> operational ErrorRecoveryLevel in the CSM-I case (please look at the
> discussion in section 3.12.2), or is dependent on the Logout reason code
> (recovery Vs close) in the CSM-E case.  All the FREE state symbolizes
> really is that the iSCSI connection is gracefully closed with a successful
> explicit/implit iSCSI Logout.  The pending tasks at this point have no
> connection allegiance, and are loosely "owned" by the session.  It is
> legitimate
> for the pending tasks to be existent (waiting for reassignment) even when
> all the connections reported FREE (please look at the discussion under
> 3.15.2, Time2Retain).
>
> Regards.
> --
> Mallikarjun
>
> Mallikarjun Chadalapaka
> Networked Storage Architecture
> Network Storage Solutions Organization
> Hewlett-Packard MS 5668
> Roseville CA 95747
>
>
> ----- Original Message -----
> From: Rahul Bhagwat
> To: ips@ece.cmu.edu
> Sent: Monday, November 05, 2001 5:31 AM
> Subject: Connection Recovery
>
>
> Hi,
>
> Is there any order in task reassignments and connection logout (implicit
or
> explicit)
> during a connection recovery.
>
> If these two are not related, what is the use of moving the connection to
> CLEANUP_WAIT
> state? CLEANUP_WAIT state typically means that there are pending tasks for
> this
> connection due to which it cannot be moved to FREE state. That is only
> difference
> betweeen FREE state and CLEANUP_WAIT state.
>
> Which probably means that it is mandatory that Task reassigment happens
> before
> logging out a failed connection (in CLEANUP_WAIT state). Once a CSM-E or a
> CSM-I
> drives the connection to free state, all the pending tasks need to be
freed
> up.
>
> Am I correct here?
>
> Regards,
> Rahul
>