6.7

Table Of Contents
Hosts Are Powered-o When Total Cluster Load Is High
Hosts are powered off when total cluster load is high.
Problem
DRS determined that virtual machines can be run on fewer hosts without degrading the host or virtual
machine performance. DRS is also constrained from moving the virtual machines running on the highly
utilized hosts to the hosts scheduled for power-off.
Cause
The total cluster load is too high.
Solution
Reduce the cluster load.
DRS Seldom or Never Performs vMotion Migrations
DRS seldom or never performs vMotion migrations.
Problem
DRS does not perform vMotion migrations.
Cause
DRS never performs vMotion migrations when one or more of the following issues is present on the
cluster.
n
DRS is disabled on the cluster.
n
The hosts do not have shared storage.
n
The hosts in the cluster do not contain a vMotion network.
n
DRS is manual and no one has approved the migration.
DRS seldom performs vMotion when one or more of the following issues is present on the cluster:
n
Loads are unstable, or vMotion takes a long time, or both. A move is not appropriate.
n
DRS seldom or never migrates virtual machines.
n
DRS migration threshold is set too high.
DRS moves virtual machines for the following reasons:
n
Evacuation of host that a user requested enter maintenance or standby mode.
n
VM/Host DRS rules or VM/VM DRS rules.
n
Reservation violations.
n
Load imbalance.
vSphere Resource Management
VMware, Inc. 143