Reservation and shares are important resource management settings in a vSphere DRS cluster. They can be set on cluster objects like VMs and resource pools to isolate resources, prioritize, and/or guarantee their availability.
To know when to set them for VMs and when to set them on resource pools, we need to understand:
- What these settings mean.
- How these settings can impact resource availability for a VM.
In this paper, VMware explains how these settings are different for a VM and resource pool while giving some general guidelines for using them.