About Host Ratings
When a virtual machine is deployed on a host in Virtual Machine Manager (VMM), all available hosts are assigned a host rating, consisting of zero through five stars, to indicate the host’s suitability for hosting the virtual machine. The host rating is based on the virtual machine's hardware and resource requirements and anticipated resource usage.
Host ratings also take into consideration one of the following placement goals, which you specify:
- Resource maximization—When resource maximization is the goal, the suitability of each virtual machine host is rated based on the intention to consolidate multiple low-utilization workloads on a single host. Virtual machine placement in these cases involves determining the capacity limits for a particular host and placing virtual machines on that host until the limits are reached.
- Load balancing—When load balancing is the goal, the suitability of each virtual machine host is rated based on the intent to minimize the processing load on any one host.
The relative importance assigned to the availability of CPU, memory, disk I/O capacity, and network capacity for the virtual machine also are factored in.
The metrics for rating hosts can be customized for Virtual Machine Manager and for individual virtual machines during deployment.