Tuesday, March 22, 2016

Increase VMware Performance and Decrease the Needed Space by Disabling the .vmem File

Dear all,
I you want to increase the I/O performance, and decrease the disk space needed to run your VM, your should consider disabling the memory swap file (.vmem).

Actually, .vmem is the virtual machine's paging file, which backs up the guest main memory on the host file system. This file exists only when the virtual machine is running, or if the virtual machine has crashed.

Therefore, if you do not want VMware to create a memory swap file, which is as large as the chosen RAM of your guest OS, go to:
C:\ProgramData\VMware\VMware Workstation\config.ini
And add the following: 
mainMem.useNamedFile = "FALSE"
prefvmx.minVmMemPct = "100"
MemTrimRate = "0"

This supposed to increase the performance of your VM; Since VMware will no more maintain duplicating your guest RAM to the hard disk. Therefore, you should notice the performance difference. Additionally, you will gain more disk space, because VMware now will not create a large file to duplicate your guest OS RAM.

However, here are something you have to pay attention for:
  • If the VM has crashed, you will not be able to restore the state of your guest OS with the running applications.
  • Suspend will take more time than before changing those configuration.
  • For suspend and resume, you still need a file with the size of the configured RAM of your gust OS. Such that, for every suspend action, VMware will create a new "<snapshot_name_and_number>.vmem" file.
You may find more info at:

Best Wishes,