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From: Christophe Varoqui <christophe.varoqui@free.fr>
To: egoggin@emc.com
Cc: dm-devel@redhat.com, christophe.varoqui@free.fr
Subject: Re: path group failback
Date: Mon, 13 Mar 2006 18:17:35 +0100	[thread overview]
Message-ID: <20060313171735.GA13642@pundit> (raw)
In-Reply-To: <C2EEB4E538D3DC48BF57F391F422779321B0E5@SRMANNING.eng.emc.com>

> > In such a scenario, wouldn't the priorizer catch priority changes ?
> 
> No, not necessarily, and certainly not for CLARiiON.  None of these
> 3 use cases involves changing which path group is the highest priority
> path group so each path in the 2 groups continue to have the same
> priority as before the externally initiated change of the active path
> group.  For each use case, only the identity of the active path group
> has been changed.
> 
I guess the priorizer *should* catch priority changes ...

> > 
> > ie, paths to owning SP are heavier than paths to not owning SP, so
> > changing the owning SP in navisphere would shuffle the path group
> > priorites.
> 
> CLARiiON path priority is dependent solely on 2 factors -- (1) the
> path must be active (or ghost) and (2) the path must connect to its
> logical unit's "default" (not necessarily active) owning service
> processor.
> 
> > 
> > If it is the case I would imagine the failback target to be the
> > externally designated one, which seems right.
> 
> No.  The CLARiiON's highest priority path group is defined to be
> the default owning service processor instead of the active service
> processor (they may or may not be the same at any given instant)
> in order to maintain the manually established distribution of
> logical units across the 2 service processors.
> 
Would it be unreasonable to teach the prioritizer about this case ?

Regards,
cvaroqui

  reply	other threads:[~2006-03-13 17:17 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-03-13 16:44 path group failback egoggin
2006-03-13 17:17 ` Christophe Varoqui [this message]
  -- strict thread matches above, loose matches on Subject: below --
2006-03-15 16:06 egoggin
2006-03-13 15:37 egoggin
2006-03-13 16:26 ` Christophe Varoqui

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