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    Re: Connection Recovery



    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
    
    


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Last updated: Tue Nov 06 01:17:30 2001
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