You can change the amount of memory resources allocated to a virtual machine by using the shares, reservations, and limits settings. The host determines the appropriate amount of physical RAM to allocate to virtual machines based on these settings. You can assign a high or low shares value to a virtual machine, depending on its load and status.

The following user-defined settings affect the memory resource allocation of a virtual machine.
Places a limit on the consumption of memory for a virtual machine. This value is expressed in megabytes.
Specifies the guaranteed minimum allocation for a virtual machine. The reservation is expressed in megabytes. If the reservation cannot be met, the virtual machine will not turn on.
Each virtual machine is granted a number of memory shares. The more shares a virtual machine has, the greater share of host memory it receives. Shares represent a relative metric for allocating memory capacity. For more information about share values, see the vSphere Resource Management documentation.

You cannot assign a reservation to a virtual machine that is larger than its configured memory. If you give a virtual machine a large reservation and reduce its configured memory size, the reservation is reduced to match the new configured memory size.


Verify that the virtual machine is turned off.


  1. Right-click a virtual machine in the inventory and select Edit Settings.
  2. On the Virtual Hardware tab, expand Memory, and allocate the memory capacity for the virtual machine.
    Option Description

    Guaranteed memory allocation for this virtual machine.


    Upper limit for this virtual machine’s memory allocation. Select Unlimited to specify no upper limit.


    The values Low, Normal, High, and Custom are compared to the sum of all shares of all virtual machines on the server.

  3. Click OK.