OpenZFS vs. the Competition


April 4, 2016


What’s in your file system?

“My data” is a reasonable answer but if you take that data seriously, you should take a moment to think about the actual underlying file system that you are trusting to keep your data safe. After all, the file system is the most critical component in doing so. The countless storage products on the market use a myriad of different “production ready” file systems, and these file systems vary dramatically in the precautions they take to guarantee the integrity of your data. From “bit rot” to machine and human error, you can assume that the majority of storage solutions are not taking any data integrity precautions beyond some form of simple redundancy. Let’s examine what the most popular file systems do and don’t do to protect your data, and why every storage solution available from iXsystems uses the OpenZFS file system.

Storage solutions broadly fall into four categories: SoHo NAS systems, Cloud-based solutions, Enterprise NAS and SAN solutions, and Microsoft Storage Server solutions. Of these, the SoHo NAS and Cloud-based solutions can have quite a bit in common because they’re both focused on delivering commodity products and services. To keep costs down, these budget-conscious “black box” solutions typically employ GNU/Linux file systems such as Ext3, Ext4, XFS and Btrfs, and hardware or software RAID for redundancy. With the exception of Btrfs, none of these components are taking any precautions against bit rot or the damage that can be done by an interrupted write to disk. They also offer primitive at best snapshotting and rollback options to mitigate human error, and do not facilitate the verifiable importing and exporting of your data. Btrfs does aim to deliver many of the features found in OpenZFS but in its current state, Btrfs suffers from space accounting issues, a limited volume manager, and general administrative complexity. A search for “Btrfs petabyte” will show that few, if any users are deploying Btrfs at scale, let alone in production.

By contrast, traditional NAS and SAN vendors like EMC and NetApp do make concerted efforts to provide data integrity guarantees but they do so using proprietary file systems that lock you into their platforms which become quite costly as they scale. The de facto IT vendor Microsoft offers ReFS as a modern alternative to the ubiquitous NTFS file system, but ReFS appears to share a fate similar to Btrfs: Not yet ready for production and not yet the default file system for Microsoft’s own storage products.


Enter OpenZFS

All of the above storage solutions represent de facto standards in one way or another and there comes a time when such standards need to be thrown out and replaced with something new. The OpenZFS project is exactly that decision and is easily the greatest achievement of Sun Microsystems’ Open Source push a decade ago. OpenZFS is a modern, Open Source file system for modern architectures, and takes more data integrity precautions than any file system before it or since. OpenZFS uses the power of modern CPUs to checksum and validate data at every step to detect data integrity errors A.K.A. “bit rot”, before they reach your application.


OpenZFS can also:

  • Repair detected bit rot with sophisticated distributed parity and mirror-based redundancy strategies
  • Alleviate machine errors with a copy-on-write architecture
  • Mitigate human error with snapshots, cloning, and rollback
  • Accelerate arrays with a hybrid flash logging and caching architecture
  • Replicate verifiably to other LAN and WAN-based OpenZFS systems
  • Scale by design beyond the capacity of contemporary hardware
  • Advance relentlessly thanks to a strong Open Source community
  • Deliver high-availability with the TrueNAS enterprise storage platform


OpenZFS is the most complete and battle-tested file system available, especially when it comes to protecting your data from corruption or loss. From the FreeNAS Mini through the multi-petabyte TrueNAS Z35, iXsystems has a storage solution powered by OpenZFS that is ready to meet your file sharing, backup, virtualization, and media needs. Visit us or call 855 GREP-4-IX (855 473-7449) to learn more about iXsystems storage solutions.

Michael Dexter
Senior Analyst

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