VMware Fusion memory overcommit

VMware Fusion is the Workstation equivalent on OSX. It has come along way but there is not the same feature parity as there is in Windows. One handy feature is the ability to overcommit memory usage. This will swap memory usageĀ from the host memory to disk when the host memory exceeds its threshold.

This is great for laptop lab warriors like myself who work offline when on planes or want to demo/test/validate something without latency.

The config file that needs to be edited or created is /Library/Preferences/VMware\ Fusion/config . This can be done with nano and you may need to sudo for write permissions.

The config file needs the following command added to it.

prefvmx.minVmMemPct = %

Where % equals a numerical value listed below. There are three levels of host memory reservation

  • 75 – which will use 75% of host memory reserved for VM, 25% being swapped
  • 50 – which will use 50% of host memory reserved for VM, 50% being swapped
  • 25 – which will use 25% of host memory reserved for VM, 75% being swapped

This can degrade the performance of your machine and strangle resources if it cannot keep up so be mindful.

This allows me to run and install the following machines on my 13″ MBP (16GB, 1TB, i7)

  • vCenter Server Appliance
  • NSX Manager
  • vSphere hosts
  • Log Insight

I have created base snapshots and created labs with the same addresses on different custom VM networks that allow me to adjust accordingly.

Leave a Reply

Your email address will not be published. Required fields are marked *