Questions on Persistent Reservations...again

ROWEBER at acm.org ROWEBER at acm.org
Fri Aug 1 13:36:08 PDT 1997


* From the T10 (formerly SCSI) Reflector (t10 at symbios.com), posted by:
* ROWEBER at acm.org
*
Steve,

} 1st... What about persistent reservations to LUN0 if it is the controller 
} device? Any thoughts on practicality of such a thing and any restrictions that 
} might want to be placed on it (by comment or spec treatment?)...in general
} the reservations are for media access, but hosts ought to know what the right
} thing to do with the controller device...

It seems to me that reserving LUN_Z (LUN0 to everybody except registered SCC 
hackers) would the perfect way to prevent another initiator from changing the 
configuration of the virtual unit LUNs.  As a confirmed control freek, I'm all 
for this kind of power.

} 2nd... How persistent to reservations need to be with respect to power-off 
} situations. The definition of this case could be power-failure and planned 
} power shutdowns. I can see where the reservations should be kept across 
} power-failures, but I am not sure it applies when someone decides to turn 
} their computer room for the weekend to save energy...I suppose it could
} be the fact that no other access is allowed providing some type security,
} but its not much...

I'm no persistent reservations expert (but I play on on TV).  Still, I could
have sworn that the APTPL bit (see Table 45 and surrounding text) pretty well 
nailed this issue down.

Thanks.

Ralph...
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