VMware vSphere vCenter Server 4.0 - Manual (Page 65)

Automation Level
Whether the host power state and migration recommendations generated by VMware DPM are executed
automatically or not depends upon the power management automation level selected for the feature.
The automation level is configured under Power Management in the cluster’s Settings dialog box. The options
available are:
n Off – The feature is disabled and no recommendations will be made.
n Manual – Host power operation and related virtual machine migration recommendations are made, but
not automatically executed. These recommendations appear on the cluster’s DRS tab in the vSphere Client.
n Automatic – Host power operations are automatically executed if related virtual machine migrations can
all be executed automatically.
N
OTE
The power management automation level is not the same as the DRS automation level.
VMware DPM Threshold
The power state (host power on or off) recommendations generated by the VMware DPM feature are assigned
priorities that range from priority-one recommendations to priority-five recommendations.
These priority ratings are based on the amount of over- or under-utilization found in the DRS cluster and the
improvement that is expected from the intended host power state change. A priority-one recommendation is
mandatory, while a priority-five recommendation brings only slight improvement.
The threshold is configured under Power Management in the cluster’s Settings dialog box. Each level you
move the VMware DPM Threshold slider to the right allows the inclusion of one more lower level of priority
in the set of recommendations that are executed automatically or appear as recommendations to be manually
executed. At the Conservative setting, VMware DPM only generates priority-one recommendations, the next
level to the right only priority-two and higher, and so on, down to the Aggressive level which generates
priority-five recommendations and higher (that is, all recommendations.)
N
OTE
The DRS threshold and the VMware DPM threshold are essentially independent. You can differentiate
the aggressiveness of the migration and host-power-state recommendations they respectively provide.
Host-Level Overrides
When you enable VMware DPM in a DRS cluster, by default all hosts in the cluster inherit its VMware DPM
automation level.
You can override this default for an individual host by selecting the host Host Options page of the cluster's
Settings dialog box and clicking its Power Management setting. You can change this setting to the following
options:
n Disabled
n Manual
n Automatic
N
OTE
Do not change a host's Power Management setting if it has been set to Disabled due to failed exit standby
mode testing.
Chapter 6 Using DRS Clusters to Manage Resources
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