Microsoft improves File System in Windows 11 24H2 but sadly it's not for everyone

Yesterday, alongside the release of the Windows 11 2024 feature update, Microsoft published feature details regarding Windows 11 LTSC 2024 and Windows 11 24H2 for managed PCs.

One of the several new features LTSC has received is VHD-based Dev Drive utilizing ReFS or Resilience File System. The feature debuted back in 2023 at Build, when the company promised up to 30% faster performance.

Today, the company announced that ReFS on Windows 11 24H2 is getting another performance improvement thanks to the new Block Cloning feature. It was already present in Server versions since 2016 but is now being introduced on client PCs as well.

It writes:

Since Dev Drive utilizes the ReFS file system format, Block cloning support = performance benefits whenever you copy a file using Dev Drive. Faster copy completion, less I/O to the underlying storage & improved storage capacity!

Block cloning refers to a technique wherein Windows creates a duplicate copy of a file's data blocks rather than copying the entire file when the said file is copied, moved, or modified and saved within the same volume. Windows identifies the file's data blocks on disk and creates a new reference to the existing data blocks. Thus, the new file points to the same data blocks as the original file.

Essentially, this improvement leads to a more efficient file system by reducing disk space usage and hastening file copy/move/modification speeds.

Neowin had already reported on this improvement when the feature was still in the works. Depending on the size of the file, initial testing showed anywhere between 18% to 94% performance improvement on ReFS with block cloning enabled compared to NTFS.

Sadly, NTFS does not have a feature like block cloning, and hence, general users will not see such improvements. Instead, it relies on features like Copy-on-write (CoW) when modifying a file or File System Reflinking when creating a new file reference to existing data blocks.

Regardless, this is definitely a real example of improvement in performance, unlike the example Microsoft had given, citing a paid study that shows ridiculous performance numbers.