z/VM: CP Commands and Utilities Reference - z/VM - IBM

SET SHARED
►►
Set
Authorization
Purpose
SHARED
Operands
Usage Notes
Responses
ON
OFF
FOR
Privilege Class: B
Use SET SHARED to control whether a full-pack minidisk is to be shared by the
users of many real and virtual systems.
ON
OFF
indicates that the device is shared or not shared among multiple real and virtual
systems.
rdev
rdev1-rdev2
is the real device number or range of real device numbers of the devices to be
shared.
1. Attention: Use SET SHARED OFF with extreme caution and only after
careful consideration.
2. You should contact the operators of the systems that are sharing the device to
assure that they mark a device as unusable in their system configuration and
physically disable their interfaces to that device before you enter the SET
SHARED OFF command.
3. You may use this command to tell CP whether to issue real reserve/release
CCWs to the device associated with the full-pack minidisk.
4. When you SET SHARED OFF for a full-pack minidisk, that device is not
released by CP. If the device is currently reserved by CP for a user, it remains
reserved until that user issues a release to that device.
5. You can determine the SHARED status of system DASD by issuing the class B
QUERY DASD RESERVE command.
6. When you SET SHARED ON for a device, minidisk caching is turned off for the
device. If minidisk caching is desired, it must specifically be set on via the SET
MDCACHE command.
7. This command will be rejected for full-pack minidisks if working allegiance (SET
WRKALLEG) has been turned on for one of the device’s associated minidisks.
Working allegiance is simulated to ensure data integrity among users sharing
the same minidisk on the same VM system. Sharing real devices on the same
minidisk is not allowed.
Response 1.:
rdev
rdev1-rdev2
SET SHARED
►◄
Chapter 2. CP Commands 1385