Operating VM groups (SU /390)

The VM2000 concept of VM groups enables the VM2000 administrator to combine multiple VMs in an organizational unit. VM groups have attributes of their own and are assigned to a CPU pool. The VMs which belong to the VM group are taken into account in a special way for scheduling.

 VM groups are not available on SU x86.

Attributes of VM groups and their members

VM groups have their own CPU quota (CPU-QUOTA operand). This determines the VM group’s share of the CPU capacity of the CPU pool in comparison to other VM groups located in the CPU pool and VMs which do not belong to a VM group. Similarly to the virtual machine, the CPU utilization of the VM group can be restricted by the maximum CPU utilization (MAX-CPU-UTILIZATION operand).

For scheduling, too, the VM group is regarded as a unit. If a VM in the VM group has not yet used up the CPU share intended for it, the other VMs of this VM group are given preference over the other VMs of the CPU pool during scheduling. This is also referred to as “load balancing within a VM group”.

The VMs which belong to a VM group are also referred to as “members of the VM group”. They have their own member CPU quota (MEMBER-CPU-QUOTA operand) which determines the CPU share of the VM compared to the other VMs in the VM group.
The maximum CPU utilization of a member VM is restricted by both the “maximum CPU utilization of the VM” and the “maximum CPU utilization of the VM group”.

Further information on the CPU quota, maximum CPU utilization and scheduling is provided in the sections "Planning distribution of the CPU capacity to the VMs" and "Scheduling procedure".

The monitor VM can also be added to a VM group.

Commands for operating VM groups

The VM2000 administrator manages a VM group in the ADMIN dialog using the monitor VM. The function and privileges of the VM2000 administrator are described in the section "Operating the whole VM2000 system".

The table below shows the individual operation groups with the associated VM2000 commands for operating a VM group.

Operation group	VM2000 command
Creating a VM group	CREATE-VM-GROUP 1
Adding a VM to a VM group	CREATE-VM 1 ADD-VM-TO-VM-GROUP 1 CREATE-VM-DEFINITION 1 2 MODIFY-VM-DEFINITION 1 2
Modifying the attributes of a VM in a VM group	MODIFY-VM-ATTRIBUTES 3
Removing a VM from a VM group	DELETE-VM 4 DELETE-VM-DEFINITION 1 2 REMOVE-VM-FROM-VM-GROUP 1
Modifying the attributes of a VM group	MODIFY-VM-GROUP-ATTRIBUTES 1 ASSIGN-VM-GROUP-TO-CPU-POOL 1
Outputting information on a VM group	SHOW-VM-GROUP 1
Deleting a VM group	DELETE-VM-GROUP 1

1	For use by the VM2000 administrator only
2	Command only for working with VM definitions
3	Command for the VM2000 administrator and those VM administrators with ADMIN-PRIVILEGES=*MAXIMUM (see "Extending and restricting the range of commands/functions")
4	For use by the VM2000 administrator and the VM administrator of the VM

   

These operation groups are described in more detail in the sections below.