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Comment by speedgoose | Hacker News Reader

It’s super slow.

If you deal with many small files on Windows, you will observe much better performances in WSL2/ext4 than windows with NTFS. Even though the ext4 filesystem is stored as a file inside a NTFS partition.

If you use NodeJS for example, it’s a very obvious speed difference.

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Is it NTFS or is it the NT I/O stack? Because the latter is so impressively complex I’m not sure if it’s actually possible for it to do fast metadata operations.

(I remember Raymond Chen writing there was a special metadata caching layer in the NT FAT driver because otherwise it would be unbearably slow. Linux has a general-purpose dentry cache playing a similar role—does modern Windows have anything similar for NTFS?)

Are there any good analysis on what makes it slow?

Practical File System Design:The Be File System covers the designs of other file systems briefly and goes from FFS to XFS, NTFS, EXT2 (book was written in the late 90s)

PDF: http://www.nobius.org/dbg/practical-file-system-design.pdf

From here: https://news.ycombinator.com/item?id=17468920

"We covered the grandfather of most modern file systems, BSD FFS; the fast and unsafe grandchild, ext2; the odd-ball cousin, HFS; the burly nephew, XFS; and the blue-suited distant relative, NTFS. Each of these file systems has its own characteristics and target audiences. BSD FFS set the standard for file systems for approximately 10 years. Linux ext2 broke all the rules regarding safety and also blew the doors off the performance of its predeces- sors. HFS addressed the needs of the GUI of the Macintosh although design decisions made in 1984 seem foolhardy in our current enlightened day. The aim of XFS is squarely on large systems offering huge disk arrays. NTFS is a good, solid modern design that offers many interesting and sophisticated features and fits well into the overall structure of Windows NT."

Thanks for the link to the book!

Yeah there's one from an ms dev here:

https://github.com/microsoft/WSL/issues/873#issuecomment-425...

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