In the latest release of PowerCLI (5.5 r2), is a new feature allowing us to set the vMotion priority of a VM. The ability to set vMotion priority is not new to vSphere. The feature was first introduced in vSphere 4.1. However, up until now, vMotions occuring through the use of the PowerCLI “Move-VM” command would only operate at standard vMotion priority.
What is vMotion Priority?
When a vMotion occurs, vCenter attempts to reserve the resources on both the source and destination hosts to be shared among all concurrent migrations. For vMotions set at High Priority, vCenter will give a greater share of host CPU resources over the Standard Priority vMotion. This is useful if there is a need to push a specific virtual machine through vMotion quicker than other VMs that are being vMotion at the same time.
vMotion Priority does not change the concurrent vMotion limits. The simultaneous vMotion limits can be seen below:
What are my options?
There are two values to choose from for the -vMotionPriority parameter
- High – Increased CPU shares given for vMotion
- Standard (Default) – No additional shares given
How do I use vMotion Priority?
The –vMotionPriority parameter is added on to the Move-VM cmdlet as seen below.
a basic example of this feature is:
Move-VM –vm <VM Name> –vMotionPriority High –destination <destination host> -runasync
*Note: vMotion Priority is a benefit realized during concurrent vMotions.