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MOOSEFS(7)        DragonFly Miscellaneous Information Manual        MOOSEFS(7)

NAME
       MooseFS - networking, distributed, fault-tolerant file system

DESCRIPTION
       MooseFS is a networking, distributed file system. It spreads data over
       several physical localisations (servers), which are visible to a user
       as one resource.  For standard file operations MooseFS acts as other
       Unix-alike file systems. It has hierarchical structure (directory
       tree), stores files' attributes (permissions, last access and
       modification times) as well as makes it possible to create special
       files (block and character devices, pipes and sockets), symbolic links
       (file names pointing to another files accessible locally, not
       necessarily on MooseFS) and hard links (different names of files which
       refer to the same data on MooseFS). Access to the file system can be
       limited basing on IP address and/or password.

       Distinctive features of MooseFS are:

        - higher reliability (data can be stored in several copies on separate
       computers)

        - dynamically expanding disk space by attaching new computers/disks

        - possibility of storing deleted files for a defined period of time
       ("trash
                 bin" service on a file system level)

        - possibility of creating snapshot of a file, which means coherent
       copy of the
                 whole file, even while the file is being written.

ARCHITECTURE
       MooseFS installation consists of four types of machines:

        - managing server (mfsmaster(8)) - single computer managing the whole
       filesystem,
                 storing metadata for every file (information on size,
              attributes and file
                 localisation(s), including all information about non-regular
              files, i.e.
                 directories, sockets, pipes and devices).

        - data servers (mfschunkserver(8)) - any number of commodity servers
       storing files
                 data and replicating it among themselves (if a certain file
              is supposed to
                 exist in more than one copy).

        - metadata backup servers (mfsmetalogger(8)) - any number of servers,
       all of
                 which store metadata changelogs and periodically downloading
              base metadata file;
                 it's easy to run mfsmaster(8) process on such machine when
              primary master
                 stops working.

        - client computers referring to MooseFS stored files - any number of
       machines with
                 working mfsmount(8) process that communicates with the
              managing server to
                 receive and modify file information and with chunkservers to
              exchange actual
                 file data.

       Metadata is stored in memory of the managing server and simultaneously
       is being saved on disk (as a periodically updated binary file and
       immediately updated incremental logs). The main binary file as well as
       the logs are replicated to metaloggers (if present).

       File data is divided to fragments (chunks) of maximum size 64MB each
       which are stored as files on selected disks on data servers
       (chunkservers). Each chunk is saved on different computers in a number
       of copies equal to a "goal" for the given file.

REPORTING BUGS
       Report bugs to <bugs@moosefs.com>.

COPYRIGHT
       Copyright 2008-2009 Gemius SA.

       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 3.

       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, see <http://www.gnu.org/licenses/>.

SEE ALSO
       mfschunkserver(8), mfsmaster(8), mfstools(1), mfsmount(8)

MooseFS 1.6.9                    November 2009                      MOOSEFS(7)