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SDLT 600 SCSI Interface Guide Chapter 4: SCSI Commands

81-81200-02 REV A01 January 2005 4-145

02h Release A PERSISTENT RESERVE 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 reservation. Sending a PERSISTENT RESERVE OUT

command that specifies a Release service action when no persistent

reservation exists from that initiator does not result in an error. Instead,

the drive returns a GOOD status without altering any other reservation;

the Release service action does not change the Reservation Key.

The drive returns a CHECK CONDITION status for any PERSISTENT

RESERVE OUT command that specifies the release of a persistent

reservation held by the requesting initiator that does not match the Scope

and Type. The Sense Key is set to ILLEGAL REQUEST and the

Additional Sense Code 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 values match an existing persistent reservation held by the initiator

making the request are not errors.

An active persistent reservation may also be released by either of the

following:

• Powering off. When the most recent APTPL value received by the

drive is 0, a power-off performs a hard reset, clears all persistent

reservations, and removes all registered Reservation Keys.

• Executing a PERSISTENT RESERVE OUT command from another

initiator with a persistent reserve service action of Clear, Pre-empt, or

Pre-empt & Clear.

Do not perform a Release service action if any operations interlocked by

the persistent reservation have not yet completed.

03h Clear A PERSISTENT RESERVE 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 drive as non-conflicting continue their

normal executions.

A UNIT ATTENTION condition is established for all registered initiators

for the logical unit. The Sense Key is set to UNIT ATTENTION and the

Additional Sense Code is set to RESERVATIONS PREEMPTED.

Applications should not use the Clear service action except during

recoveries associated with initiator or system reconfiguration as this may

compromise data integrity.

Table 4-83. PERSISTENT RESERVE OUT Command’s Service Action Descriptions (Continued)

Code Name Description

1 2 ... 182 183 184 185 186 187 188 189 190 191 192 ... 293 294

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