6.5.1

Table Of Contents
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
anity 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 anity rules.
n
Compute the sum of the reservations of all the virtual machines in the anity rule. If that value is
greater than the available capacity on any host, the rule cannot be satised.
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 satised 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 insucient resources or because there are no
compatible hosts for the virtual machine.
Solution
If the cluster does not have sucient resources to power on a single virtual machine or any of the virtual
machines in a group power-on aempt, 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 insucient resources on the
host.
Problem
When you power on a virtual machine, DRS does not migrate it as expected when there are not enough
resources on the host where the virtual machine is registered.
Cause
The following are possible reasons why DRS does not move the virtual machine.
n
DRS is disabled on the virtual machine.
n
The virtual machine has a device mounted.
n
The virtual machine is not compatible with any other hosts.
n
No other hosts have a sucient number of physical CPUs or capacity for each CPU for the virtual
machine.
n
No other hosts have sucient CPU or memory resources to satisfy the reservations and required
memory of this virtual machine.
n
Moving the virtual machine will violate an anity or anti-anity rule.
Chapter 17 DRS Troubleshooting Information
VMware, Inc. 135