Microsoft Enhances File System in Windows 11 24H2, But Not Everyone Benefits

On the same day as the launch of the Windows 11 2024 feature update, Microsoft unveiled feature details related to Windows 11 LTSC 2024 and Windows 11 24H2, specifically designed for managed PCs.

Among the notable new features in LTSC is the VHD-based Dev Drive, which utilizes the ReFS (Resilient File System). This feature was first introduced at the Build conference in 2023, where Microsoft highlighted performance enhancements of up to 30%.

Recently, Microsoft revealed that ReFS in Windows 11 24H2 is set to receive another performance upgrade through the introduction of the Block Cloning feature. While this functionality has been present in server versions since 2016, it is now making its way to client PCs.

According to the update:

Since Dev Drive leverages the ReFS file system format, Block cloning support equates to performance improvements whenever files are copied using Dev Drive. This results in quicker copy completion, reduced I/O to the underlying storage, and enhanced storage capacity!

Block cloning is a method where Windows duplicates only the data blocks of a file rather than the entire file when performing actions like copying, moving, or modifying a file within the same volume. The operating system recognizes the data blocks on disk and creates a new reference to those existing blocks. Hence, the new file references the same data blocks as the original.

Ultimately, this enhancement leads to a more efficient file system by minimizing disk space utilization and accelerating the speeds of copy/move/modification operations.

Preliminary testing indicates that, depending on the file size, performance improvements on ReFS with block cloning enabled can range from 18% to 94% compared to NTFS.

Unfortunately, NTFS lacks a feature similar to block cloning, meaning that the average user will not benefit from such enhancements.

Nonetheless, this is a concrete example of performance improvement, distinctly different from other claims made by Microsoft referencing a paid study that presented questionable performance statistics.

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