Table 5-115presents the definitions of the characters of the available “Type” values from the Type field of the PERSISTENT RESERVATION IN Read Reservations parameters.

Each of the codes provides handling instructions for READ operations, for WRITE operations, and for subsequent attempts to establish persistent reservations (referred to as “Additional Reservations Allowed” in the table).

Table 5-115Persistent Reservation Type Codes and Their Meanings

Code

Name

Description

 

 

READS: Shared; any application client on any initiator may execute commands that

 

 

perform transfers from the disk to the initiator.

0h

READ Shared

WRITES: Prohibited; any command from any initiator that performs a transfer from the

initiator to the disk results in a reservation conflict.

 

 

ADDITIONAL RESERVATIONS: Allowed; any initiator may reserve the logical unit,

 

 

extents, or elements as long as the persistent reservations do not conflict with any res-

 

 

ervations already known to the device server.

 

 

READS: Shared; any application client on any initiator may execute commands that

 

 

perform transfers from the disk to the initiator.

 

WRITE Exclu-

WRITES: Exclusive; any command from any initiator other than the initiator that holds

1h

the persistent reservation that attempts a transfer to the disk results in a reservation con-

sive

flict

 

 

 

ADDITIONAL RESERVATIONS: Allowed; any initiator may reserve the logical unit,

 

 

extents, or elements as long as the persistent reservations do not conflict with any res-

 

 

ervations already known to the device server.

 

 

READS: Exclusive; any command from any initiator other than the initiator that holds

 

 

the persistent reservation that attempts a transfer from the disk results in a reservation

 

 

conflict

2h

READ Exclusive

WRITES: Shared; any application client on any initiator may execute commands that

perform transfers to the disk from the initiator.

 

 

 

 

ADDITIONAL RESERVATIONS: Allowed; any initiator may reserve the logical unit,

 

 

extents, or elements as long as the persistent reservations do not conflict with any res-

 

 

ervations already known to the device server.

 

 

READS: Exclusive; any command from any initiator other than the initiator holding the

 

 

persistent reservation that attempts a transfer from the disk results in a reservation con-

 

 

flict.

 

 

WRITES: Exclusive; any command from any initiator other than the initiator holding

 

 

the persistent reservation that attempts a transfer to the disk results in a reservation con-

3h

Exclusive Access

flict.

 

 

 

ADDITIONAL RESERVATIONS: Restricted; any PERSISTENT RESERVATION

 

 

OUT command with the Reserve service action from any initiator other than the initiator

 

 

holding the persistent reservation results in a reservation conflict. The initiator that

 

 

holds the persistent reservation can reserve the logical unit, extents, or elements as long

 

 

as the persistent reservations do not conflict with any reservations already known to the

 

 

device server.

Maxtor Atlas 10K V

5-87