Usage mode of pubsets

Exclusive use (usage mode EXCLUSIVE)

A pubset is used exclusively when it is assigned to only one VM and cannot be assigned to any other.

Exclusive use is said to apply in the following cases:

• The pubset is assigned to the VM explicitly by /ADD-VM-DEVICES UNITS=*PUBSET-DEVICES(...), TYPE=*NONE.

• Exclusive use is set with /MODIFY-VM-DEVICE-USAGE UNITS=*PUBSET-DEVICES(...),USAGE=*EXCLUSIVE.

• Shared use of disks of a pubset is converted to exclusive use when the disks are assigned implicitly and only to this VM and the pubset is imported exclusively to this VM in the guest system  (/IMPORT-PUBSET ...,USAGE=*EXCLUSIVE).

/MODIFY-VM-DEVICE-USAGE UNITS=*PUBSET-DEVICES(...),USAGE=*SHARED can be used to set shared use for a pubset (but not for the home pubset) that is used exclusively by a VM.

Inputs/outputs for exclusively assigned devices take place directly between the guest system and the pubset device.

Shared use (usage mode SHARED)

Shared use describes the situation where a pubset is assigned to at least one VM and can be assigned to other VMs, see also the section "Shared disk devices".

Shared use is said to apply in the following cases:

• The pubset is assigned to the VM explicitly by /ADD-VM-DEVICES UNITS=*PUBSET-DEVICES(...), TYPE=*SD.

• The pubset is assigned to the VM implicitly.

• Shared use is set with/MODIFY-VM-DEVICE-USAGE UNITS=*PUBSET-DEVICES(...),USAGE=*SHARED

• When a pubset which is used exclusively is exported (/EXPORT-PUBSET), exclusive use of the disks of the pubset is converted to shared use if the disks are assigned implicitly to the VM (reversal of the procedure for /IMPORT-PUBSET...,USAGE=*EXCLUSIVE).

A pubset that is assigned to a VM for shared use can be assigned to the VM exclusively by means of /MODIFY-VM-DEVICE-USAGE UNITS=*PUBSET-DEVICES(...),USAGE=*EXCLUSIVE, provided it is not already assigned to any other VM.

The usage mode of a pubset entered for the VM in its VM definition can be modified with /MODIFY-VM-DEFINITION. Detailed information can be found in the section "Working with VM definitions".

For information on input/output handling for the devices of shared pubsets, please refer to the paragraph “Input/output handling for shared devices” in the section "Usage mode of a device".