mhddfs.1

.TH mhddfs "1" "February 2008"
.SH NAME
mhddfs \- The driver combines a several mount points into the single one.
.SH 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
.SS 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

.SH OPTIONS

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

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

.SS loglevel=x
0 \- debug messages

1 \- info messages

2 \- standard (default) messages
.SS 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:
.RS
[mM] \- megabytes

[gG] \- gigabytes

[kK] \- kilobytes
.RE
.PP
For an information about the additional options see output of:
.RS
.B mhddfs \-h
.RE

.SH DESCRIPTION
.PP
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
.B unionfs
but it can choose a drive with the most of free space, and move the
data between drives transparently for the applications.
.PP
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.
.PP
.B df 
will show a total statistics of all filesystems like there is a
big one hdd.
.PP
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.
.PP
.SS 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 
.B sshfs
systems together.

Please read FUSE documentation for a further conception.

.SH COPYRIGHT
Distributed under 
.B GPLv3

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