Block Size to Use with Hyper-V Environment

Q: What block size should I use in my virtual machine, on my CSV, and so on?

A: The best guidance is to use a 64KB block size for everything, which will ensure the best performance, because when you deal with virtualization you're dealing with large VHD and VHDX files.

• On the storage, use 64KB stripe sizes.
• Use 64KB cluster size on file system on the host.
• Use 64KB cluster size on the file system within the virtual machine.

VHD uses a block size of 2MB and VHDX uses a block size of 32MB, which are both multiples of 64KB. This will provide the best overall performance.