NAME

       mhddfs - The driver combines a several mount points into the single one.

SYNOPSIS

        mhddfs /dir1,/dir2[,/path/to/dir3] /path/to/mount [-o options]
        mhddfs /dir1 dir2,dir3 /mount/point [-o options]
        ...
        fusermount -u /path/to/mount

   fstab record example:
       mhddfs#/path/to/dir1,/path/to/dir2 /mnt/point fuse defaults 0 0

       mhddfs#/dir1,/dir2,/dir3 /mnt fuse logfile=/var/log/mhddfs.log 0 0

OPTIONS

       with an -o option1,option2...  you can specify some additional options:

   logfile=/path/to/file.log
       specify a file that will contain debug information.

   loglevel=x
       0 - debug messages

       1 - info messages

       2 - standard (default) messages

   mlimit=size[m|k|g]
       a free space size threshold If a drive has the free space less than the threshold specifed
       then another drive will be choosen while creating a new file.  If all the drives have free
       space  less  than  the threshold specified then a drive containing most free space will be
       choosen.

       Default value is 4G, minimum value is 100M.

       This option accepts suffixes:
              [mM] - megabytes

              [gG] - gigabytes

              [kK] - kilobytes

       For an information about the additional options see output of:
              mhddfs -h

DESCRIPTION

       The file system allows to unite a several mount points (or directories) to the single one.
       So  a one big filesystem is simulated and this makes it possible to combine a several hard
       drives or network file systems. This system is like unionfs but it can choose a drive with
       the  most  of  free  space,  and  move  the  data  between  drives  transparently  for the
       applications.

       While writing files they are written to a 1st hdd until the hdd has the  free  space  (see
       mlimit option), then they are written on a 2nd hdd, then to 3rd etc.

       df will show a total statistics of all filesystems like there is a big one hdd.

       If  an  overflow arises while writing to the hdd1 then a file content already written will
       be transferred to a hdd containing enough of free space for a file.  The  transferring  is
       processed  on-the-fly,  fully  transparent  for  the  application that is writing. So this
       behaviour simulates a big file system.

   WARNINGS
       The filesystems are combined must provide a possibility to get their parameters  correctly
       (e.g.  size  of free space). Otherwise the writing failure can occur (but data consistency
       will be ok anyway). For example it is a bad  idea  to  combine  a  several  sshfs  systems
       together.

       Please read FUSE documentation for a further conception.

COPYRIGHT

       Distributed under GPLv3

       Copyright (C) 2008 Dmitry E. Oboukhov <dimka@avanto.org>

                                          February 2008                                 mhddfs(1)