DRS affinity rules

DRS affinity rules are used in DRS clusters to control the placement of virtual machines. Three types of rules are available:

• affinity rules – DRS will try to keep certain VMs together on the same host. These rules are often used in multi-virtual machine systems to localize the traffic between virtual machines.
• anti-affinity rules – DRS will try to keep certain VMs are not on the same host. These rules are often used to keep the VMs separated for availability reasons.
• VM to host rules – specify whether VMs can or can’t be run on a host. They can be preferential or required. These rules are used in conjunction with DRS groups for ease of administration. A DRS group can either consist of one or more VMs or one or more ESXi hosts.