You can change the amount of memory resources allocated to a virtual machine by using the shares, reservations, and limits settings.

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 power 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.

Assigning a reservation to a virtual machine that is larger than its configured memory is wasteful. The vSphere Web Client prevents you from making such an assignment on the Resources tab. If you give a virtual machine a large reservation and reduce its configured memory size on the Hardware tab, the reservation is reduced to match the new configured memory size. You must power off the virtual machine before configuring memory resources.


Select a virtual machine.

In the virtual machines and templates inventory tree, select a group of virtual machines and select a virtual machine from the list on the right.

Search for a virtual machine and select it from the search results list.


In the VM Hardware panel, click Edit Settings.


Click Virtual Hardware.


Click the Memory triangle to expand the memory options.


Allocate the memory capacity for the virtual machine.




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.


Click OK.