ReFS (Resilient File System) is a file system developed by Microsoft for Windows, designed to improve data integrity, scalability, and resilience compared to NTFS. It was introduced back in 2012 with the Windows Server 2012 release.
Over the years, Microsoft has improved ReFS significantly. After the initial release in 2012, Microsoft released an updated version with better performance and stability, tiered storage support, and faster metadata operations in 2013.
With Windows Server 2016, Microsoft announced a major update with support for block cloning (instant file copy for VMs and databases), sparse VDL (Valid Data Length) for faster virtual disk creation, improved Hyper-V integration, and more. With Windows Server 2019 and Windows Server 2022, Microsoft further improved ReFS with performance enhancements, improved repair and integrity performance, and more.
Today, Microsoft announced that ReFS boot support is now available for Windows Server Insiders in Insider Preview builds. With this, users can install and boot Windows Server directly on a ReFS boot volume. This is the first time Microsoft is enabling boot support for ReFS nearly 14 years after its launch.
Microsoft claims that ReFS boot will enable several advantages over existing NTFS boot. For example, ReFS can detect corruption early and handle file-system issues online without requiring chkdsk. Also, its integrity-first design can reduce the risk of crash-induced corruption. While current NTFS systems support large volumes, ReFS can now support volumes up to 35 petabytes (35,000 TB) to eliminate storage capacity issues.
Finally, ReFS uses block cloning and sparse provisioning, allowing enterprises to easily create and expand large fixed-size VHD(X) files and speed up large file copy operations.
Here"s how enterprises can try out ReFS boot support on Windows Server:
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Install the recent Windows Server vNext Insider Preview. Builds from 2/11/26 or later (minimum build number 29531.1000.260206-1841) include ReFS boot in setup.
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During the install process, format the system (C:) partition as ReFS in the installation UI. Microsoft highlighted that ReFS boot requires UEFI firmware and does not support legacy BIOS boot.
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Once the installation is completed and the system boots, confirm the ReFS file system by checking the C drive properties.
ReFS boot support is a significant step for enterprise deployments, offering organizations a modern file system alternative to NTFS, which has been the standard for decades.