Reference Guide

Chapter 4 SCSI Commands
PERSISTENT RESERVE OUT Command (5Fh)
DLT-S4 Interface Reference Guide 223
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, Preempt, or Preempt & Abort.
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.
Code Name Description