A vSphere administrator notices that hosts are not powering off when the total cluster load is low on a cluster configured with Dynamic Power Management. What condition could cause this behavior?

Dynamic Power Management (DPM) works by relying on DRS to migrate all virtual machines off an underutilized host before initiating a power-off. When the DRS migration threshold is set to its most conservative setting, DRS will only migrate VMs for very large load imbalances and will not proactively consolidate VMs off lightly loaded hosts, which blocks DPM from ever fully evacuating a host and prevents it from issuing any power-off commands.

The most aggressive DRS threshold permits frequent migrations for even minor load imbalances, which would actively assist DPM in consolidating workloads and powering off idle hosts - the opposite of the described symptom.

A conservative DPM threshold raises the power-savings bar required to trigger a shutdown, but if DRS has already consolidated VMs and left a host empty, DPM would still eventually act; the DRS threshold is the upstream blocker that prevents hosts from ever becoming empty.

The most aggressive DPM threshold causes DPM to power off hosts even for small power-saving opportunities, which would increase the frequency of host power-offs rather than prevent them.