6.7

Table Of Contents
Cause
VM/VM DRS rules specify that selected virtual machines should be placed on the same host (affinity) or
that virtual machines be placed on different hosts (anti-affinity). VM/Host DRS rules specify that selected
virtual machines should be placed on specified hosts (affinity) or that selected virtual machines should not
be placed on specified hosts (anti-affinity).
When a VM/VM DRS rule or VM/Host DRS rule is violated, it might be because DRS cannot move some
or all of the virtual machines in the rule. The reservation of the virtual machine or other virtual machines in
the affinity rule, or their parent resource pools, might prevent DRS from locating all virtual machines on
the same host.
Solution
n
Check the DRS faults panel for faults associated with affinity rules.
n
Compute the sum of the reservations of all the virtual machines in the affinity rule. If that value is
greater than the available capacity on any host, the rule cannot be satisfied.
n
Compute the sum of the reservations of their parent resource pools. If that value is greater than the
available capacity of any host, the rule cannot be satisfied if the resources are obtained from a single
host.
Virtual Machine Power On Operation Fails
An error message appears stating that the virtual machine fails to power on.
Problem
The virtual machine fails to power on.
Cause
The virtual machine might fail to power on because of insufficient resources or because there are no
compatible hosts for the virtual machine.
Solution
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, check the resources required by the virtual machine against those
available in the cluster or its parent resource pool. If necessary, reduce the reservations of the virtual
machine to be powered-on, reduce the reservations of its sibling virtual machines, or increase the
resources available in the cluster or its parent resource pool.
DRS Does Not Move the Virtual Machine
DRS does not move the virtual machine when it is initially powered on despite insufficient resources on
the host.
vSphere Resource Management
VMware, Inc. 149