VMM Pro is primarily designed for multi-NAS cluster management and business continuity. Do I need a licence to run VMM? - Synology Community

Synology VMM Pro is an advanced virtualization solution designed for Synology NAS devices. It offers a range of features that enhance the capabilities of the standard VMM package, including:

Synology often offers a 30-day free trial of VMM Pro directly within the VMM application settings. This is the safest way to test cluster features without risking your data.

is sufficient. It allows for basic virtualization, snapshots, and running Linux or Windows VMs without a paid license. VMM Pro License