(A New) Persistent Reservation Question

Roger Cummings roger.cummings at veritas.com
Fri Oct 27 08:49:23 PDT 2000


* From the T10 Reflector (t10 at t10.org), posted by:
* Roger Cummings <roger.cummings at veritas.com>
*
Folks,

I have a question about the definition of Persistent Reservations in SPC-2
that I don't believe is covered by anything currently in 00-267r2. The
question is related  to the following:

The 6th paragraph of 5.5.3.5 (with the response to Quantum #402 included)
says:

"If the device server receives a PERSISTENT RESERVE OUT command with a
service action of RESERVE where
the TYPE and SCOPE are the same as the existing TYPE and SCOPE from the
initiator that created the persistent reservation,
it shall not make any change to the existing reservation and shall return a
GOOD status."

I'm not sure that I can parse this sentence correctly, but at face value it
appears to conflict with Table 9, where any Reserve command  received where
the addressed LU has a reservation from a different initiator gets a
conflict.

Is the 6th paragraph of 5.5.3.5 intended to refer ONLY to a second reserve
that is IDENTICAL in type, scope and source (initiator) to an existing
reservation ??

What I'm worried about is this situation:

1) There's an existing Registrants Only (RO) LU reservation to LU 1 from
registered Initiator A.
2) An identical RO LU reservation to LU 1 is received from Registered
Initiator B.

can the reservation in 2) get a Good (allowed) response, per 5.5.3.5 ???

Note the prior reservation doesn't need to change to grant B access [because
the reservation in 1) allows Initiator B full access anyway].

To look at this from another way, does it really make sense that the
reservation in 2) above gets a conflict when just about any other command
that Registered Initiator B sends will be allowed ?? Surely it would be
better, in the case where the rights granted under the new reservation would
be IDENTICAL to the existing reservation, to allow the command and not
change the existing reservation (i.e. make the response allowed in the 3rd
column of table 9 and have a note similar to the one for Release).

Regards,







Roger Cummings
VERITAS Software

roger.cummings at veritas.com
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