6.0

4 For any host that fails to exit standby mode successfully, select the host in the cluster Settings dialog
box’s Host Options page and change its Power Management setting to Disabled.
After you do this, vSphere DPM does not consider that host a candidate for being powered off.
Using DRS Affinity Rules
You can control the placement of virtual machines on hosts within a cluster by using affinity rules.
You can create two types of rules.
n
Used to specify affinity or anti-affinity between a group of virtual machines and a group of hosts. An
affinity rule specifies that the members of a selected virtual machine DRS group can or must run on the
members of a specific host DRS group. An anti-affinity rule specifies that the members of a selected
virtual machine DRS group cannot run on the members of a specific host DRS group.
See “VM-Host Affinity Rules,” on page 367 for information about creating and using this type of rule.
n
Used to specify affinity or anti-affinity between individual virtual machines. A rule specifying affinity
causes DRS to try to keep the specified virtual machines together on the same host, for example, for
performance reasons. With an anti-affinity rule, DRS tries to keep the specified virtual machines apart,
for example, so that when a problem occurs with one host, you do not lose both virtual machines.
See “VM-VM Affinity Rules,” on page 366 for information about creating and using this type of rule.
When you add or edit an affinity rule, and the cluster's current state is in violation of the rule, the system
continues to operate and tries to correct the violation. For manual and partially automated DRS clusters,
migration recommendations based on rule fulfillment and load balancing are presented for approval. You
are not required to fulfill the rules, but the corresponding recommendations remain until the rules are
fulfilled.
To check whether any enabled affinity rules are being violated and cannot be corrected by DRS, select the
cluster's DRS tab and click Faults. Any rule currently being violated has a corresponding fault on this page.
Read the fault to determine why DRS is not able to satisfy the particular rule. Rules violations also produce
a log event.
NOTE VM-VM and VM-Host affinity rules are different from an individual host’s CPU affinity rules.
Create a Host DRS Group
A VM-Host affinity rule establishes an affinity (or anti-affinity) relationship between a virtual machine DRS
group with a host DRS group. You must create both of these groups before you can create a rule that links
them.
Prerequisites
Launch the vSphere Client and log in to a vCenter Server system.
Procedure
1 In the vSphere Client, right-click the cluster in the inventory and select Edit Settings.
2 In the left pane of the cluster Settings dialog box under vSphere DRS, select DRS Groups Manager.
3 In the Host DRS Groups section, click Add.
4 In the DRS Group dialog box, type a name for the group.
5 In the left pane, select a host and click >> to add it to the group. Continue this process until all desired
hosts have been added.
You can also remove hosts from the group by selecting them in the right pane and clicking <<.
6 Click OK.
Chapter 25 Resource Management for Single Hosts
VMware, Inc. 365