libfuse is an Hurd-specific implementation of FUSE, initially written by Stefan Siegl.

The implementation takes advantage of the translators facilities of Hurd: this means that applications that implement a FUSE filesystem, when compiled against libfuse-hurd, become translators to be set with usual settrans etc.

Status

Only part of the API is implemented
- lowlevel API not implemented
- Options handling (fuse_parse_cmdline and fuse_opt_*) not implemented
- CUSE lowlevel not supported (compatibility level 29)
Supports the compatibility level 25 and 26, up to libfuse 2.6.x
File I/O is quite slow.

IRC, freenode, #hurd, 2013-05-31

<zacts> well the reason I'm asking, is I'm wonder about the eventual
  possibility of zfs on hurd
<pinotree> no, zfs surely not
<zacts> *wondering
<zacts> pinotree: would that be because of license incompatabilities, or
  technical reasons?
<pinotree> the latter
<taylanub> It's just a matter of someone sitting down and implementing it
  though, not ?
<pinotree> possibly
<braunr> zacts: the main problem seems to be the interactions between the
  fuse file system and virtual memory (including caching)
<braunr> something the hurd doesn't excel at
<braunr> it *may* be possible to find existing userspace implementations
  that don't use the system cache (e.g. implement their own)
<braunr> and they could almost readily use our libfuse version

IRC, freenode, #hurd, 2013-10-01

<pinotree> our libfuse implementation is still basic atm (there's a wiki
  page about it)
<alsuren> okay... talk to me about FUSE
<pinotree> even with the improvements i have in my public branch, it still
  cannot do real-world fs'es
<alsuren> okay, so you're the person to ask about FUSE
<alsuren> it strikes me that HURD not having FUSE support is a bit of an
  architectural oversight
<pinotree> i'm not sure what's your point about fuse, since what fuse on
  linux (and not only) does is done *natively* by the hurd
<alsuren> exactly
<pinotree> all of the hurd filesystems (which are just a type of servers)
  run in userspace already
<alsuren> so FUSE should Just Work
<pinotree> well no

Source

incubator, libfuse/master.