With the announcement and write-up of ReFS (Resilient File System) on places like arstechnica, I am curious to know what technology, or technology stack, exists for Linux/Unix for a similar outcome.

ReFS is designed to pick up where Storage Spaces leave off. To protect its internal data structures, file system metadata, and, optionally, user data against corruption, ReFS calculates and stores checksums for the data and metadata. Each piece of information protected by the checksum is fed into a checksum algorithm, and the result is a number, the checksum; in ReFS's case, the checksum is a 64-bit number. Checksum algorithms are designed such that a small change in the input causes a large change in the resulting checksum.

Every time ReFS reads file system metadata (or data that has opted in to the checksum protection) it will compute the checksum for the information it has read, and compare this against the stored value. If the two are in agreement then the data has been read correctly; if they aren't, it hasn't.

So - is there anything comparable for Linux/Unix? Is it really just ZFS for Windows? If not, how does it differ?

  • Also maybe how this differs from something like ZFS/Btrfs (which uses checksums for data verification as well) – Wayne Jan 17 '12 at 23:13
  • @Wayne - I've updated the question with your feedback – warren Jan 17 '12 at 23:15
  • also curious - why the "close" vote (to whomever voted)? – warren Jan 17 '12 at 23:16
  • 2
    Admittedly, neither btrfs or ReFS is prime-time ready. They both lack necessary features to be used as the one and only FS. It's still few years too early for that, on both platforms. The only production grade, general purpose filesystem with checksumming is ZFS. – Hubert Kario Jan 17 '12 at 23:22

When I first read the announcement, I immediately thought of ZFS, as it has had, for years, many of the features touted as groundbreaking by ReFS.

Don't get me wrong, though - Windows badly needs a new filesystem, and this seems to be going in the right direction.

Is it really just ZFS for Windows?

No, not really. On the surface, they share a similar feature set, but they are drastically different architecturally. ReFS is based on NTFS, wheras ZFS (as far as I can tell) was designed from the ground up, with no obvious filesystem ancestors.


ZFS and btrfs both implement data and metadata integrity through checksums (as well as a some of other features which ReFS may have "borrowed" - the "scrubbing" sounds very familiar somehow) - the latter of which is not yet stable for general use.

Edit: Yeah, they've even mentioned these on that Ars article that you linked.


There are also fossil+venti in Plan 9 world which implement content-addressed storage and a filesystem layer on top of that. It's there since 2002.

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