VMware DRS is a feature of vCenter Server on the properties of a cluster that balances load across multiple ESX/ESXi hosts. It has the following two main functions:
To decide which node of a cluster should run a virtual machine when it's powered on, a function often referred to as intelligent placement
To evaluate the load on the cluster over time and either make recommendations for migrations or use VMotion to automatically move virtual machines to create a more balanced cluster workload
Fortunately, if you like to retain control, you can set how aggressively DRS will automatically move virtual machines around the cluster.
If you start by looking at the DRS properties—you can view these properties by right-clicking ...