Maxtor ATLAS 15K Product Manual page 152

SCSI Description
Code Name
02h Release
03h Clear
5-86 Maxtor Atlas 15K
A PERSISTENT RESERVATION OUT command with Release service action removes a
persistent reservation held by the same initiator.
The fields associated with a Release service action match fields of the active persistent res-
ervation. Sending of a PERSISTENT RESERVATION OUT command that specifies a Re-
lease service action when no persistent reservation exists from that initiator does not result
in an error. Instead, the device server returns a GOOD message without altering any other
reservation: the reservation key is not changed by the Release service action.
The device server returns a CHECK CONDITION status for any PERSISTENT RESER-
VATION OUT command that specifies the release of a persistent reservation held by the
requesting initiator that matches some but not all of the Scope, Type, Reservation Key, and
extent values. The sense key is set to ILLEGAL REQUEST and additional sense data is set
to INVALID RELEASE OF ACTIVE PERSISTENT RESERVATION. Attempts to release
persistent reservations in which none of the Scope, Type, Reservation Key, and extent val-
ues match an existing persistent reservation held by the initiator making the request are not
errors.
An active persistent reservation may also be released by:
1. Powering off. When the most recent APTPL value received by the device server is 0, a
power-off performs a hard reset, clears all persistent reservations, and removes all registered
reservation keys;
or
2. Executing a PERSISTENT RESERVATION OUT command from another initiator with
a persistent reserve service action of Pre-empt or Pre-empt and Clear.
Note that a Release service action should not be performed if any operations interlocked by
the persistent reservation have not yet completed.
A PERSISTENT RESERVATION OUT command with a successful Clear service action
removes all persistent reservations for all initiators. All reservation keys are also removed.
Any commands from any initiator that have been accepted by the device server as non-con-
flicting continue their normal executions.
A UNIT ATTENTION condition is established for all initiators for the cleared logical unit.
The sense key is set to UNIT ATTENTION; the additional sense data is set to RESERVA-
TIONS PREEMPTED.
Note that applications should not use the Clear action service except during recoveries as-
sociated with initiator or system reconfiguration, since data integrity may be compromised.
Description