Considering the following Wikipedia information and other data found on the internet as well, we decided to implement Windows 10 Storage Spaces Two-Way Mirror using plain NTFS, but wanted to know if the landscape has improved for recovery of this relatively new file system.

What is below is the excerpt from Wikipedia that this question is referencing (they made it sound like an impossible problem to solve):

ReFS -- Stability and known problems https://en.wikipedia.org/wiki/ReFS#Stability_and_known_problems  

Issues identified or suggested for ReFS, when running on Storage Spaces (its intended design[13]), include:

Adding thin-provisioned ReFS on top of Storage Spaces (according to a 2012 pre-release article) can fail in a non-graceful manner, in which the volume without warning becomes inaccessible or unmanageable.[11] This can happen, for example, if the physical disks underlying a storage space became too full. Smallnetbuilder comments that, in such cases, recovery could be "prohibitive" as a "breakthrough in theory" is needed to identify storage space layouts and recover them, which is required before any ReFS recovery of file system contents can be started; therefore it recommends using backups as well.[11]

Even when Storage Spaces is not thinly provisioned, ReFS may still be unable to dependably correct all file errors in some situations, because Storage Spaces operates on blocks and not files, and therefore some files may potentially lack necessary blocks or recovery data if part of the storage space is not working correctly. As a result, disk and data addition and removal may be impaired, and redundancy conversion becomes difficult or impossible.[12]

There are no tools to repair or recover a ReFS filesystem. Third party tools are dependent on reverse engineering the system and (as of 2014) few of these exist.[13][22].

Also, can Windows 10 boot to a Two-Way Storage Spaces? Thanks.

1 Answer 1


Recovery of RAID systems including Storage Spaces should be from a backup. Mirroring is for availability and performance not recovery.

Storage Spaces are not supported as boot volumes.

ReFS features are primarily for data centre and virtualization use cases. If you are considering ReFS on Windows 10 take another look at the feature list and decide if you actually need what it offers. For most workstation scenarios NTFS is still the file system to choose.

  • 1. Regarding "Recovery of RAID systems including Storage Spaces should be from a backup." I worked for a company that was sabotaged in its backups, so that DEFINITELY didn't work. Sometimes backups fail (at least at one job, this actually happened -- a PDP-11.) BOTTOM LINE: Sometimes you have no other choice than to try to recover from the disk. And if ReFS on Storage Spaces makes it impossible, as it sounds, then I will use just plain NTFS on Storage Spaces. Dec 23, 2019 at 16:50
  • 2. Regarding "Mirroring is for availability and performance not recovery." -- Mirroring is for what we will use it for, or more importantly, for what our big customers are telling me what they are using it for, and they are using it to always have a backup of their critical data. That is, if one disk of the mirrored pair fails, the other disk will most likely still be fine. I agree that backups should also be done, but it's not my company, and all I know is that they said to set the machine up using two-way mirroring on Storage Spaces. It was up to us to use ReFS / NTFS. Dec 23, 2019 at 16:54
  • 3. Regarding "Storage Spaces are not supported as boot volumes." -- Thank you for confirming for me that this is (still) true. Dec 23, 2019 at 16:55
  • 4. Went with NTFS on a two-way mirrored Storage Spaces basic drive implemented on two 3-TB disks. Dec 23, 2019 at 16:56
  • "should" denotes primary or best, not only - if the backup was sabotaged (or otherwise not viable) this option is not available so you should move on to the next best viable approach which may very well be file system recovery. If your customers are telling you what they are doing, it's likely your job to tell them how to do it correctly - what you describe is availability not backup. That might be just a matter of discussing terminology with them and setting expectations. I recently did the same with a client to differentiate a data backup from a data refresh... happens often.
    – Doug
    Dec 31, 2019 at 6:13

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