Userspace S3 filesystem
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Latest commit 40e5396 May 2, 2018

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RioFS is an userspace filesystem for Amazon S3 buckets for servers that run on Linux and MacOSX. It supports versioned and non-versioned buckets in all AWS regions. RioFS development started at Skoobe as a storage backend for legacy daemons which cannot talk natively to S3. It handles buckets with many thousands of keys and highly concurrent access gracefully.


  • C compiler
  • glib >= 2.22
  • fuse >= 2.7.3
  • libevent >= 2.0
  • libxml >= 2.6
  • libcrypto >= 0.9
  • libmagic (optional: --with-libmagic=PATH)

Find here installation guides for Ubuntu, Centos and MacOSX


sudo make install


export AWS_ACCESS_KEY_ID="your AWS access key"
export AWS_SECRET_ACCESS_KEY="your AWS secret access key"
riofs [options] [bucketname] [mountpoint]


-v: Verbose output.
-f: Do not daemonize process.
-c path: Path to configuration file.
-o "opt[,opt...]": fuse options
-l path: Log file to use.
--uid: Set UID of filesystem owner.
--gid: Set GID of filesystem owner.
--fmode: Set mode for files.
--dmode: Set mode for directories.


  • In order to allow other users to access a mounted directory:

    • make sure /etc/fuse.conf contains user_allow_other option

    • launch RioFS with -o "allow_other" parameter

  • On OS X it is recommended to run RioFS with the -o "direct_io" parameter

  • Default configuration is located at $(prefix)/etc/riofs.conf.xml

  • Use ./configure --with-libmagic=PATH to guess the content-type of uploaded content (requires libmagic)

  • Use ./configure --enable-debug to create a debug build

  • RioFS comes with a statistics server, have a look at riofs.xml.conf for details

  • Send a USR1 signal to tell RioFS to reread the configuration file

  • Send a USR2 signal to tell RioFS to reopen log file (useful for logrotate)

  • Send a TERM signal to unmount filesystem and terminate running RioFS instance (example: killall riofs)

Known limitations

  • Appending data to an existing file is not supported.

  • Folder renaming is not supported.

  • A file system for the S3 API is a leaky abstraction. Don't expect POSIX file system semantics.


  • Any help is welcome, just open an issue if you find a bug

  • We also need better documentation, testing, tutorials and benchmarks