Should DRS Affinity Rules be disabled when upgrading ESXi hosts in a cluster

Products

• VMware vSphere ESXi

Issue/Introduction

• There are DRS Affinity Rules configured in a cluster to keep certain Virtual Machines (VMs) together on the same host (affinity) or apart (anti-affinity) for performance or availability.
• ESXi hosts need to be upgraded in that cluster which has DRS affinity rules configured.

Environment

• VMware vCenter Server 8.x
• VMware vSphere ESXi 8.x

Resolution

'Must' DRS affinity rules should be disabled on the cluster when upgrading ESXi hosts. 'Should' DRS affinity rules can be kept in enabled state because they allow automatic VM relocation during host patching and return them without manual action, reducing the potential for human error.