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Table Of Contents
If the cluster does not have sufficient resources to power on a single virtual machine, or any of the virtual
machines in a group power-on attempt, a message appears. Otherwise, for each virtual machine, DRS
generates a recommendation of a host on which to run the virtual machine and takes one of the following
actions
n
Automatically executes the placement recommendation.
n
Displays the placement recommendation, which the user can then choose to accept or override.
Note No initial placement recommendations are given for virtual machines on standalone hosts or in
non-DRS clusters. When powered on, they are placed on the host where they currently reside.
n
DRS considers network bandwidth. By calculating host network saturation, DRS is able to make
better placement decisions. This can help avoid performance degradation of virtual machines with a
more comprehensive understanding of the environment.
Single Virtual Machine Power On
In a DRS cluster, you can power on a single virtual machine and receive initial placement
recommendations.
When you power on a single virtual machine, you have two types of initial placement recommendations:
n
A single virtual machine is being powered on and no prerequisite steps are needed.
The user is presented with a list of mutually exclusive initial placement recommendations for the
virtual machine. You can select only one.
n
A single virtual machine is being powered on, but prerequisite actions are required.
These actions include powering on a host in standby mode or the migration of other virtual machines
from one host to another. In this case, the recommendations provided have multiple lines, showing
each of the prerequisite actions. The user can either accept this entire recommendation or cancel
powering on the virtual machine.
Group Power-on
You can attempt to power on multiple virtual machines at the same time (group power-on).
Virtual machines selected for a group power-on attempt do not have to be in the same DRS cluster. They
can be selected across clusters but must be within the same data center. It is also possible to include
virtual machines located in non-DRS clusters or on standalone hosts. These virtual machines are
powered on automatically and not included in any initial placement recommendation.
The initial placement recommendations for group power-on attempts are provided on a per-cluster basis.
If all the placement-related actions for a group power-on attempt are in automatic mode, the virtual
machines are powered on with no initial placement recommendation given. If placement-related actions
for any of the virtual machines are in manual mode, the powering on of all the virtual machines (including
the virtual machines that are in automatic mode) is manual. These actions are included in an initial
placement recommendation.
vSphere Resource Management
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