[dm-devel] path group failback

[Christophe Varoqui]

> > 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