Using the vSphere Client you can view information about and make changes to memory allocation settings. To administer your memory resources effectively, you must also be familiar with memory overhead, idle memory tax, and how ESXi hosts reclaim memory.
When administering memory resources, you can specify memory allocation. If you do not customize memory allocation, the ESXi host uses defaults that work well in most situations.
You can specify memory allocation in several ways.
Use the attributes and special features available through the vSphere Client. The vSphere Client user interface allows you to connect to the ESXi host or vCenter Server system.
Use advanced settings.
Use the vSphere SDK for scripted memory allocation.