Understanding memory allocation for VMware Fusion

Products

• VMware Desktop Hypervisor

Issue/Introduction

Understanding the way Mac OS X allocates memory can help to identify potential problems. It also gives you a more comprehensive understanding of how Fusion and its virtual machines use the Mac's memory.

This article provides information about system memory (RAM). For information about disk space, see Investigating disk space in Mac OS X (1021932).

When using VMware Fusion, you may notice these symptoms:

• The virtual machine does not return the free memory when it is suspended.
• The virtual machine continues to use the memory, even when it is not running.

Environment

• VMware Fusion 3.x
• VMware Fusion 2.x
• VMware Fusion 4.x
• VMware Fusion 5.x

Resolution

• When a virtual machine is powered on, it uses 128MB for the video RAM when using the SVGA driver. When a virtual machine is powered on, it uses 256MB for the video RAM when using the WDDM driver. This is in addition to the RAM allocated to the virtual machine.
• When a virtual machine is powered down, it is assumed that you will not be starting it any time soon. Therefore, the majority of the memory is returned to inactive memory. This ensures that other programs can use the available memory.
• When a virtual machine is suspended, it is assumed that you may resume the virtual machine a few moments later. Therefore, the contents are stored in the active memory to ensure a much quicker loading when you resume the virtual machine. While Fusion is running, the suspended virtual machine's memory state will remain in active memory. When Fusion is shut down, then the virtual machine's memory state (which is stored on the hard drive for later use) is moved into inactive memory.

Additional Information

Investigating disk space in Mac OS X