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Some doubts in Persistent Reservation

DISCUSSION djshetty 2 participants 2 messages Nov 24, 2006 SCSI

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djshetty

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Hi,

I have been trying to understand PERSISTENT RESERVATION as per SCSI SPC-3 standards. I had the following two doubts:
1. Is persistent reservation applied on a target port or on a particular
LUN connected to a target port. The SCOPE of persistent reservation says "Entire LOGICAL UNIT", whereas the registration is done for a target PORT. Hence the confusion.
2. Is there any precise use of the PRGeneration key? I guessed it must be
used for knowing whether any changes have been on the target (with regards to persistent reservation) since the previous command executed.

Regards,
Dhiraj.

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Quoted 4 lines · djshetty

1. Is persistent reservation applied on a target port or on a particular
LUN connected to a target port. The SCOPE of persistent reservation says "Entire LOGICAL UNIT", whereas the registration is done for a target PORT. Hence the confusion.

For multi-ported devices it's per LUN per port (unless you specify all target ports).

Quoted 3 lines

2. Is there any precise use of the PRGeneration key? I guessed it must be
used for knowing whether any changes have been on the target (with regards to persistent reservation) since the previous command executed.

That's the stated use in section 5.6.5.3 of SPC-3, yes.

James