Load Balancing

On systems configured with two nodes, HA Load Balancing distributes VMs across both PMs to improve performance and availability. Load balancing is configured per VM and is enabled automatically on ztC Edge systems. (Systems configured with one node do not provide load balancing.) If a PM is out of service, all VMs will run on the surviving PM.  VMs automatically migrate back as soon as the PM they are targeted to run on returns to service and is fully synchronized.

Modes of Operation

Load balancing is set for a VM on its Load Balance tab on the Virtual Machines page.  The following modes are supported:

• automatically balance. This provides automatic load balancing of a VM. When a VM is set to balance automatically, it will run on the available PM with the most resources. When the system determines that better load balancing can be achieved by moving one or more VMs with the automatic setting, an alert is generated. The alert appears on the Dashboard, and a Load Balancing notification appears on the masthead. In response to the alert, click Load Balance in the masthead to initiate automatic load balancing of a VM.
  The icon on the Virtual Machines page under Current PM column indicates VMs that will migrate imminently.
• manually place on nodeN. Advanced users can manually assign a preferred PM (node) for each individual VM, rather than relying on the automatic policy, if preferred.

A graphic appears on the Virtual Machine page in the Current PM column for each VM. It indicates the current status of the VM’s load-balancing state, the PM the VM is running on, and its preference.

The following sample graphic indicates that the VM is currently on PM 0 and that PM 1 is the preference.

ztC Edge policy ensures that a VM is always running.  In the event that one PM is predicted to fail, is under maintenance, or is taken out of service, the VM will run on the healthy PM. When both PMs are healthy, a VM migrates to its preferred PM.