Q: How do I turn off integrity streams for a file in ReFS?

A: To disable integrity streams on a file in Resilient File System (ReFS)—for example, a VHD used by Hyper-V—run the following command:

Set-FileIntegrity -FileName <file name> -Enable $False

The reason this is required is that with integrity streams each write becomes multiple writes. This becomes a performance issue for VHDs used by Hyper-V and therefore needs to be disabled.