FUSE With Linux 5.15 Now Allows Mounting An Active FUSE Device

[trapexit]

Now with the new NTFS driver being merged into mainline Linux kernel, what use is FUSE these days?

People need to remember that FUSE at its core is just a protocol like 9P. As such the general hate / dismissal of it is odd given 9P's relative popularity and use. Is libfuse the best userland library or well maintained? Not really. Are there lots of random FUSE based projects that aren't that good or stable? Yes. But that's not FUSE itself.

There is a lot that can be done with FUSE and with some enhancements, like file descriptor passthrough or better interfaces to transfer data, it could be quite performant in certain usecases. My own project in particular. That said for *most* usecases the tradeoffs with performance are acceptable. Perhaps not with the recent interest in my project from the Chia farming folks but other than that the flexibility outweighs the perf concerns.

[rabcor]

CERN?

FUSE is gonna be the next project to boot us into another dimension

[phuclv]

Now with the new NTFS driver being merged into mainline Linux kernel, what use is FUSE these days?

One important usecase is to mount filesystems with block size larger than page size. For example it's not possible to mount ext4 with 8KB block size on most platforms (probably except on M1 with 16KB page) and you have to use FUSE for that

[edgmnt]

FUSE used to be really slow, well beyond the context switching overhead. Is this still the case?

[Developer12]

[QUOTE=uid313;n1277573]Now with the new NTFS driver being merged into mainline Linux kernel, what use is FUSE these days?/QUOTE]

Widely used for a variety of virtual filesystems. Everything from sshfs to the expression of hierarchical datastructures into the "everything is a file" metaphor. Hugely useful for these VFS use cases, easy to spin up, and very few of these applications have strong performance needs (at which point you go for a kernel filesystem driver, particularly if actually touching disk).

NTFS is really the LAST thing people use FUSE for these days. So many useful tools expressed as filesystems.

[RahulSundaram]

FUSE used to be really slow, well beyond the context switching overhead. Is this still the case?

Performance has improved over time but if you are really running into situations where performance is a primary concern, any FUSE based solutions is always going to be ill suited.

[archsway]

One important usecase is to mount filesystems with block size larger than page size. For example it's not possible to mount ext4 with 8KB block size on most platforms (probably except on M1 with 16KB page) and you have to use FUSE for that

Similarly, it can also be useful for mounting ext4 filesystems which use newer features when you are stuck on an old kernel. When I was in that situation I also considered using SSHFS to mount the disk image from another computer, but I think I ended up using (a somewhat modified) ext4fuse.

[mtk0]

google drive (google-drive-ocamlfuse)!

[uxmkt]

Are there any file system that FUSE supports that the kernel does not?

More than you think. If anything, FUSE has garnered the momentum (9pfs being added to Linux about the same timeframe as FUSE). if I had to wager a guess, it probably has to do with API/protocol complexity. Because if not, the world would have been writing all those lovely fuse servers as programs that instead speak NFS, CIFS or AFS
edit:: ... (or 9p for that matter). Perhaps the problem is that you can't mount nfs,cifs,afs,9p without root privileges - quite unlike fuse.

[edgmnt]

Performance has improved over time but if you are really running into situations where performance is a primary concern, any FUSE based solutions is always going to be ill suited.

I see. I think a small performance penalty consistent with context switching (say 5%) is acceptable. It might not be for very high performance stuff, if you care about extracting every last bit of useful work out of the hardware. FUSE filesystems used to be a whole lot worse, though.