ReFS in 2022

I’m wondering if anyone has experience with the ins and outs of ReFS on Windows. The motherboard in my home truenas box just kicked the bucket and I’m wondering how I want to rebuild. I could host truenas in a hyper-v VM and pass the physical disks through, or I could switch to ReFS for hosting my files.

I’m interested in discussing the technical merits and pitfalls of ReFS. I know ZFS pretty well, but I don’t know too much about ReFS other than the fact that it’s a checksumming file system. I also know the redundancy setup is handled at the volume level, as opposed to ZFS where it’s lower at the vdev level. So one pool of drives has the ability to host striped, mirrored or RAID5/6 volumes concurrently on the same physical disks. This offers more freedom to a home gamer like myself when they want to add drives. Also there’s the ability to remove drives, which ZFS just can’t do.

If anyone knows any other interesting tidbits about ReFS, or any big gotchas, I’d love to hear them. Hope to learn some new things. :slight_smile:

I’m going to be watching this thread, highly interested.

I know you want to have integrity streams turned on+enforced which apparently isn’t a default with refs to get more zfs-like integrity. from my understanding the integrity checking is good but actual errors aren’t handled very gracefully, usually creating a blocking read error; at this point I suppose you’d run a manual scrub on the underlying raid to fix the issue. I’m not sure how much of a problem with would be in practice, imo if you’re getting even 1 read error in a year there is something fundamentally wrong with your setup.

Also don’t use the bleeding edge builds of refs in the insider preview builds, they aren’t yet compatible with the MS recovery toolchain.

Reddit is probably the best place to see people talking about recent experiences, and quite frankly I see too much stuff from within the past two years that tells me to stay the hell away.

This one in particular is good to look through:

  • Checksumming must be manually enabled
  • Going to have to figure out how to get a report of a problem
  • Going to have to know powershell and how to solve your own problems pretty well if things go tits up. Think obscure Linux problem with absolutely no “here’s how to fix that exact issue” posts to be found.
  • There are ongoing ReFS/Windows version compatibility issues that are too complex for me to summarize or care about learning.

Howevrr, despite what it looks like, Microsoft is in fact still slowly working on ReFS, but do not expect something truly consumer stable anytime soon, and don’t expect it to be a replacement for NTFS ever.

If you still want to continue, this this tutorial seems solid:

My own personal path to data integrity on windows, was just to have NTFS in a VM on top of ZFS.


IIRC, they automatically checksum metadata, but you have to manually enable it for data data.

And it looks like it relies on parity form storage spaces to recover from detected corruption.

But, it does look like it will try to automatically heal when it does detect corruption (good copies existing of course)

Also, looks like ReFS is not for consumers… suposed to be for server only, so I don;t know what hoops one needs to jump through.

When Win10 was new, the pro version pretty easily allowed creating storage space parity arrays, and formatting the space as ReFS, but I thought they removed it.

Would be glad to hear both are still available in win10 / 11?

Huh, also:

The following features are unavailable on ReFS at this time:

Functionality ReFS NTFS
File system compression No Yes
File system encryption No Yes

Bootable No Yes
Page file support No Yes

Yeah, they did remove it from windows pro quite a while ago. While I never used it or intended to, I was not a fan of the hard removal of a feature.

You currently need either windows server, windows enterprise, or windows “Pro for Workstations”. Presumably it should be available on the equivalent version of 11, but I’m not familiar with win11 at all as I’ve been thoroughly ignoring it lol.


I’ve used it before for a while, then I switched to TrueNAS. I’m aware of the “checksumming not enabled on data by default”, but it’s not hard to address when you’re first setting up a Pool.

It’s available in Windows 10/11 Pro for Workstations.

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I was still using windows back when 10 released, and played around with mirrored storage spaces, with ReFS on them, and it seemed okay,
But switched not long after, and kinda lost touch, apart from hearing they were depreciating the creation of either storage spaces on normal windows, or some such.

much obliged though

There have been a couple Windows updates in the past 6 months that caused Windows to be unable to mount ReFS volumes.


You mean fake zfs


Interesting opinion since it seems to be nothing like ZFS other than having checksumming.

Alright, let me re-phrase this then. I’m going to run ReFS as a personal experiment. What sort of tests would people like to see that would prove its resiliency?

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I still have a Mirrored Storage Space with ReFS on it running on the current version of Windows 11. I had originally formatted this volume with Windows Server but then migrated to Win 10 Pro and Win 11 Pro and it continued to work.

All they seem to have removed is the support for formatting it. Because I could still spin up a Hyper-V VM with Microsoft’s own Developer Win11 Enterprise image, pass a new Storage Space through to that VM, format it as ReFS and now also have Tiered Storage (Mirrored on SSDs, Parity on HDDs) with ReFS running. Although I currently loose sync/ a disk if I start using it with huge transfers. One of my USB-HDD enclosures seems to fail (waiting on arrival of replacement for now).

I did not realize Data-Integrity was not on by default, but I will attempt to enable that when I get back home again.

I don’t think you can turn it on retro-actively for data you already have, but you can create a new folder, turn it on for that, and then move your files into it and they’ll get checksummed as they’re moved. Just FYI, a “been there, done that” for me. :wink:

Oh that’s clever, I wanted to play with the tiered storage, but I couldn’t figure out how to turn it on with Pro for Workstations.

Well all I’ll say about refs is that windows update broke it a few months back.

So I would not use in production…

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Is this the issue you’re referring to, or is there something else?

Pretty sure it was a june update and it wasn’t removable media. Think it was clustered refs volumes. Like you’d use in a hyperV cluster.

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The tiered storage itself was possible with PowerShell commands on Pro. I only needed the VM for formatting with ReFS. I can link the 2 websites I used for inspiration and a guide which PowerShell commands to look at later…

Of course that unofficial support could go away at some point without warning, but so far it has not…


It does the same pool interactions. And some framework stuff is similar, at least from when I played with ZFS on my sun machine in OBSD6

I want to see the max iops it can handle on spinning drives for a long period of time and see if it drops data stream at all. I am thinking about setting up windows as a server OS because I am too stupid to use linux as a server OS.

I’ll see what I can do. 2 of my 6 drives are SMR though, so I’m not sure how good my numbers will be.

I didn’t realize ReFS needed to be so tightly coupled with windows storage spaces in order to work as intended. I wish they could have integration with hardware raid so that it could be more performance oriented.

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