You can control the migration recommendations that vSphere DRS can generate or apply. Each migration recommendation generated by DRS will have a priority level associated with it based on the level of load imbalance in the cluster.
The migration threshold will determine which priority recommendations are to be displayed or applied. The threshold can be modified on the cluster settings page.
This is done on a DRS enabled ESXi cluster. So make sure you have access to the vCenter managing the intended DRS cluster.
The following procedure will guide you through the steps required to set a migration threshold: