Tuesday, April 18, 2017

Heavy Disk Activity after Suspending a VMWare Virtual Machine Instance

I observed heavy disk activity when I suspended a VMware virtual machine instance. The VMware software is VMware Player 7.1.4 and the virtual machine instance is a Windows XP instance. The disk activity is so heavy that it almost renders the host machine non-responsive for a quite while. After some research online, I found these configuration options to be helpful,

mainMem.useNamedFile = "false"
mainMem.writeZeroes = "true"

You can apply these two configuration options in two different manners.
  • Apply them to a specific virtual machine instance by adding these two lines to the virtual machine configuration file, i.e., a .vmx file.
  • Apply them as the global and default options for all virtual machine instances by adding these two lines to VMware software's configuration file. For VMWare Player, it is %PROGRAMDATA%\VMWare\VMware Player\config.ini. If the file does not exist, you should create it. For other versions of VMware software, see this VMware KnowledgeBase article.

To understand why and how these may address the heavy disk activity issue and whether you should use these options, the following are a few excellent references that I came across in my research.
  1. VMware Workstation and Very High VMEM Fragmentation
  2. Maximize VMWare images performance
  3. Write Activity to .vmem file even though the VM is suspended
  4. Why does my PC slow down to a crawl when VMware Player is suspending to .vmem file?