Clearing effects table for FC-Tape

Binford, Charles charles.binford at symbios.com
Mon Jul 6 06:40:38 PDT 1998


* From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
* "Binford, Charles" <charles.binford at symbios.com>
*
Many actions effect multiple ports in the table because of the SCSI
queueing model.  Clear Task Set, for example, is defined by T10 to clear
IOs for ALL initiators.  When that functionality is mapped to a
multiported FC node running FCP that means IOs received from multiple
ports are cleared.  Other actions such as power cycle and reset will
obviously effect multiple ports.

Charles Binford
Symbios Inc.
316-636-8566

> -----Original Message-----
> From:	Rob Basham [SMTP:robbyb at us.ibm.com]
> Sent:	Wednesday, July 01, 1998 4:25 PM
> To:	T10 at symbios.com
> Subject:	Clearing effects table for FC-Tape
> 
> * From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
> * Rob Basham <robbyb at us.ibm.com>
> *
> 
> Dave,
> This is a comment on the Clearing effects table for FC-Tape.  I have a
> question.  Why do so many actions affect more than just the one port
> on which
> the Initiator Action takes place?  It seems that with the wrong
> hardware
> defect, this has the potential to take down all ports (effectively) to
> the tape
> drive, reducing the "value add" of alternate ports for high
> availability.
> 
> Also, with the wrong topology choice I could envision a single
> initiator action
> on one loop cascading and causing problems on all loops.  Even with
> smart
> topology choices, it can at least cascade to the next loop over in a
> common
> dual loop topology.
> Regards,
> Rob
> 
> *
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