Now that you have tested high availability in the event of a failure occurring in a virtual machine, you can examine a scenario in which the failure occurs in a host.

When the status of a host is Non-Operational, the host remains accessible from the Red Hat Enterprise Virtualization Manager but cannot serve as a member of a cluster. A Non-Operational status signifies that a logical network is down, storage is inaccessible to the host, the type of the host CPU is incompatible with the cluster, or that the host has no logical network.

A non-operational host effects the virtualization environment in several ways. First, if a virtual machines attempts to access a non-operational host, it will be placed into a Pause state. Second, all highly available virtual machines will live migrate to another, available host in a cluster. However, only virtual machines that are in an Up state are migrated in this manner; virtual machines in a Pause state are not live migrated to prevent data corruption. Last of all, if the non-operational host is an SPM host, the SPM role will be transferred to another host in a data center.

This section demonstrates high availability when a host is non-operational due to being disconnected from the system's external storage resource. You can examine the outcomes of two different cases - when the host is acting as the Storage Pool Manager (SPM), and when it is not.

Before you begin these demonstrations, ensure that all your virtual machines are running. In addition, check which host has been configured as the SPM by clicking Hosts on the Tree pane. In this example, the Pacific host is the SPM.