MooseFS is a fault-tolerant distributed file system. It spreads data over several physical locations (servers), which are visible to user as one resource. For standard file operations MooseFS acts as any other Unix-alike filesystem: • Hierarchical structure (directory tree) • Stores POSIX file attributes (permissions, last access and modification times) • Supports special files (block and character devices, pipes and sockets) • Symbolic links (file names pointing to target files, not necessarily on MooseFS) and hard links (different names of files that refer to the same data on MooseFS) • Access to the file system can be limited based on IP address and/or password Distinctive features of MooseFS are: • High reliability (several copies of the data can be stored on separate physical machines) • Capacity is dynamically expandable by adding new computers/disks • Deleted files are retained for a configurable period of time (a file system level ”trash bin”) • Coherent snapshots of files, even while the file is being written/accessed