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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 direct mail to me (radek@podgorny.cz) as a backup.

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).

1. plain make

Just issue `make` - this compiles the code with some static settings (xattrs enabled, hard-coded libfuse2, ...) tuned for my linux system.

2. 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.