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MooseFS – A Petabyte Distributed File System

MooseFS is a Petabyte Open Source Network Distributed File System. It is easy to deploy and maintain, highly reliable, fault tolerant, highly performing, easily scalable and POSIX compliant.

MooseFS spreads data over a number of commodity servers, which are visible to the user as one resource. For standard file operations MooseFS acts like ordinary Unix-like file system:

  • A hierarchical structure – directory tree
  • Stores POSIX file attributes – permissions, last access and modification times, etc.
  • Supports ACLs
  • Supports POSIX and BSD file locks – including support for distributed file locking
  • Supports special files – block and character devices, pipes and sockets
  • Supports symbolic links – file names pointing to target files, not necessarily on MooseFS
  • Supports hard links – different names of files which refer to the same data on MooseFS

Distinctive MooseFS features:

  • High reliability – files are stored in several copies on separate servers. The number of copies is a configurable parameter, even per each file
  • No Single Point of Failure – all hardware and software components may be redundant
  • Parallel data operations – many clients can access many files concurrently
  • Capacity can be dynamically expanded by simply adding new servers/disks on the fly
  • Retired hardware may be removed on the fly
  • Deleted files are retained for a configurable period of time (a file system level "trash bin")
  • Coherent, "atomic" snapshots of files, even while the files are being written/accessed
  • Access to the file system can be limited based on IP address and/or password (similarly as in NFS)
  • Data tiering – supports different storage policies for different files/directories in Storage Classes mechanism
  • Per-directory, "project" quotas – configurable per RAW space, usable space, number of inodes with hard and soft quotas support
  • Apart from file system storage, MooseFS also provides block storage (mfsbdev)
  • Efficient, pure C implementation
  • Ethernet support

Supported platforms

MooseFS can be installed on any POSIX compliant operating system including various Linux distributions, FreeBSD and macOS:

  • Ubuntu
  • Debian
  • RHEL / CentOS
  • OpenSUSE
  • FreeBSD
  • macOS
  • Raspbian – Raspberry Pi 3

MooseFS Linux Client uses FUSE. MooseFS macOS Client uses FUSE for macOS.

There is a separate MooseFS Client for Microsoft Windows available, built on top of Dokany.

Getting started

You can install MooseFS using your favourite package manager on one of the following platforms using officially supported repositories:

  • Ubuntu 16 / 18 / 20
  • Debian 8 / 9 / 10
  • RHEL / CentOS 7 / 8
  • FreeBSD 11 / 12
  • macOS 10.11+
  • Raspbian 8 / 9 – Raspberry Pi 3

Packages for Ubuntu 14 and CentOS 6 are also available, but no longer supported.

Minimal set of packages, which are needed to run MooseFS:

  • moosefs-master MooseFS Master Server for metadata servers,
  • moosefs-chunkserver MooseFS Chunkserver for data storage servers,
  • moosefs-client MooseFS Client – client side package to mount the filesystem.

Source code

Feel free to download the source code from our GitHub code repository!

Install the following dependencies before building MooseFS from sources:

  • Debian/Ubuntu: sudo apt install build-essential libpcap-dev zlib1g-dev libfuse3-dev pkg-config (if you don't have FUSE v. 3 in your system, use sudo apt install build-essential libpcap-dev zlib1g-dev libfuse-dev pkg-config)
  • CentOS/RHEL: sudo yum install gcc make libpcap-devel zlib-devel fuse3-devel pkgconfig (if you don't have FUSE v. 3 in your system, use sudo yum install gcc make libpcap-devel zlib-devel fuse-devel pkgconfig)

Recommended packages:

  • Debian/Ubuntu: sudo apt install fuse3 (if you don't have FUSE v. 3 in your system, use sudo apt install fuse)
  • CentOS/RHEL: sudo yum install fuse3 (if you don't have FUSE v. 3 in your system, use sudo yum install fuse)

Building MooseFS on Linux can be easily done by running ./ Similarly, use ./ in order to build MooseFS on FreeBSD and respectively ./ on macOS. Remember that these scripts do not install binaries (i.e. do not run make install) at the end. Run this command manually.

Minimal setup

Just three steps to have MooseFS up and running:

1. Install at least one Master Server

  1. Install moosefs-master package
  2. Prepare default config (as root):
    cd /etc/mfs
    cp mfsmaster.cfg.sample mfsmaster.cfg
    cp mfsexports.cfg.sample mfsexports.cfg
  3. Prepare the metadata file (as root):
    cd /var/lib/mfs
    cp metadata.mfs.empty metadata.mfs
    chown mfs:mfs metadata.mfs
    rm metadata.mfs.empty
  4. Run Master Server (as root): mfsmaster start
  5. Make this machine visible under mfsmaster name, e.g. by adding a DNS entry (recommended) or by adding it in /etc/hosts on all servers that run any of MooseFS components.

2. Install at least two Chunkservers

  1. Install moosefs-chunkserver package

  2. Prepare default config (as root):

    cd /etc/mfs
    cp mfschunkserver.cfg.sample mfschunkserver.cfg
    cp mfshdd.cfg.sample mfshdd.cfg
  3. At the end of mfshdd.cfg file make one or more entries containing paths to HDDs / partitions designated for storing chunks, e.g.:


    It is recommended to use XFS as an underlying filesystem for disks designated to store chunks. More than two Chunkservers are strongly recommended.

  4. Change the ownership and permissions to mfs:mfs to above mentioned locations:

    chown mfs:mfs /mnt/chunks1 /mnt/chunks2 /mnt/chunks3
    chmod 770 /mnt/chunks1 /mnt/chunks2 /mnt/chunks3
  5. Start the Chunkserver: mfschunkserver start

Repeat steps above for second (third, ...) Chunkserver.

3. Client side: mount MooseFS filesystem

  1. Install moosefs-client package

  2. Mount MooseFS (as root):

    mkdir /mnt/mfs
    mount -t moosefs mfsmaster: /mnt/mfs

    or: mfsmount -H mfsmaster /mnt/mfs if the above method is not supported by your system

  3. You can also add an /etc/fstab entry to mount MooseFS during the system boot:

    mfsmaster:    /mnt/mfs    moosefs    defaults,mfsdelayedinit    0 0

There are more configuration parameters available but most of them may stay with defaults. We do our best to keep MooseFS easy to deploy and maintain.

MooseFS, for testing purposes, can even be installed on a single machine!

Additional tools

Setting up moosefs-cli or moosefs-cgi with moosefs-cgiserv is also recommended – it gives you a possibility to monitor the cluster online:

  1. Install moosefs-cli moosefs-cgi moosefs-cgiserv packages (they are typically set up on the Master Server)
  2. Run MooseFS CGI Server (as root): mfscgiserv start
  3. Open http://mfsmaster:9425 in your web browser

It is also strongly recommended to set up at least one Metalogger on a different machine than Master Server (e.g. on one of Chunkservers). Metalogger constantly synchronizes and backups the metadata:

  1. Install moosefs-metalogger package
  2. Prepare default config (as root):
    cd /etc/mfs
    cp mfsmetalogger.cfg.sample mfsmetalogger.cfg
  3. Run Metalogger (as root): mfsmetalogger start

Refer to installation guides for more details.

Some facts

Contact us

Copyright (c) 2008-2021 Jakub Kruszona-Zawadzki, Core Technology Sp. z o.o.

This file is part of MooseFS.

MooseFS is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, version 2 (only).

MooseFS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with MooseFS; if not, write to the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02111-1301, USA or visit


MooseFS – Open Source, Petabyte, Fault-Tolerant, Highly Performing, Scalable Network Distributed File System (Software-Defined Storage)

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