unionfs-fuse
This is my effort to create a unionfs filesystem implementation which is way more flexible than the current in-kernel unionfs solution.
I'm open to patches, suggestions, whatever...
The preferred way is the github issue tracker with the mailing list at [email protected] as backup. Or see http://groups.google.com/group/unionfs-fuse.
Why choose this stuff
- The filesystem has to be mounted after the roots are mounted when using the standard module. With unionfs-fuse, you can mount the roots later and their contents will appear seamlesly
- You get caching (provided by the underlying FUSE page cache) which speeds things up a lot for free
- Advanced features like copy-on-write and more
Why NOT choose it
- Compared to kernel-space solution we need lots of useless context switches which makes kernel-only solution clear speed-winner (well, actually I've made some tests and the hard-drives seem to be the bottleneck so the speed is fine, too)
How to build
You can either use plain make or cmake (pick one).
- plain make
Just issue make - this compiles the code with some static settings (xattrs enabled, hard-coded libfuse2, ...) tuned for my linux system.
- cmake
mkdir build
cd build
cmake ..
make
This should allow for compilation on wider variety of systems (linux, macos, ...) and allows to enable/disable some features (xattrs, libfuse2/libfuse3, ...).
To see the list of all options, run cmake -LAH after the cmake .. step.
Example of option usage:
cmake .. -DWITH_LIBFUSE3=FALSE -DWITH_XATTR=FALSE
MacOS support
unionfs-fuse has been successfully compiled and run on MacOS (with the help of macfuse - formerly osxfuse).
Since I have no access to Apple hardware+software I'm only dependent on other people's contributions.
When building for MacOS on MacOS, the "cmake option" is the recommended one.
For the linux-based development I've managed to create a limited MacOS testing environment with Vagrant (see below) but it took me absurd amount of time and was so much pain in the ass I have no further intention to waste a single minute more on closed-source systems. Thanks Apple for reminding me of my old days with Windows and how horrible time it was. ;-)
To run the vagrant-based macos tests, just execute ./test_vagrant_macos.sh.
This depends on a custom vagrant box. You can use the one I've built or you can build your own - all the required stuff should be in macos_vagrant directory.