In Windows 10 Pro Storage Space, why can't I use ReFS with Parity?

Question

NTFS is the only option when Parity is selected as the resiliency type. I thought ReFS was suppose to replace NTFS? I am trying to create a storage space to use for network file share.

Answer 1

According to discussion at Storage Spaces, Parity and ReFS

• ReFS in storage spaces is available only for two-way and three-way mirroring until Windows 10 Anniversary update incl.
  • see Wolfrevo's answer for workaround
• Creators update brought support for ReFS parity storage space
• Fall Creators update removes ReFS entirely from storage spaces
  • the AllowRefsFormatOverNonmirrorVolume workaround no longer works
  • all the ReFS functionality was moved to Windows 10 Pro for Workstations

Answer 2

Format with ReFS is turned off by default in client versions of Windows (8/8.1/10). You can turn it on modifying registry keys:

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MiniNT]
"AllowRefsFormatOverNonmirrorVolume"=dword:00000001

and

[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem]
"RefsDisableLastAccessUpdate"=dword:00000001

after that you can format any suitable volume with ReFS

Answer 3

Because of low rep I can't comment on the existing answer that refers to setting the MiniNT registry key.

This key (HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\MiniNT) should not be present on a running Windows NT installation because many Windows components will think it is running on the Preinstallation Environment and act (or not act) accordingly. I did and broke the following until I removed it:

• Windows Hello authentication GUI (credentialuibroker.exe) will pretty much break (with NonAppContainerFailedMip). It will work on a "text only" console, just like if it were W95. This will cascade and spill over all the system.
• Intune sync to a corporate AAD will fail with error 0x801901ad
• Unable to create password recovery disk
• DISM will refuse to run stating "DISM does not support servicing Windows PE with the /Online option."

All those issues will dissappear once the MiniNT key is removed. No reboot required in most cases.

Answer 4

You may not be able to select parity, as ReFS has Built-in resilience as NTFS does not have the same.

ReFS creates 64-bit checksum, with this in mind the mirrored volumes self check and heal where possible.

I would say this is why you cannot select a parity option for ReFS.