lessfs is a deduplicating filesystem. If you store files that have the same content, lessfs saves the data only once. Additionaly lessfs compresses the content and can also encrypt content and metadata.
Example with Opensuse 11.2:
Add repository and install lessfs:
zypper ar http://download.opensuse.org/repositories/filesystems/openSUSE_11.2/ repo-filesystems zypper refresh zypper in fuse-lessfs
Copy the example config and edit it matching your needs:
cp /usr/share/doc/packages/fuse-lessfs/etc/lessfs.cfg /etc/ vi /etc/lessfs.cfg
With the example config you will get filesystem data in /data/dta and metadata in /data/mta. Use
to learn more about the options.
Create the directories:
mkdir -p /data/dta mkdir -p /data/mta
lessfs /etc/lessfs.cfg /mnt
Check if you can see the filesystem with df or mount. If something goes wrong you should check the the system log (/var/log/messages).
Unmounting can be done with
I use it as backup storage for many systems with rsnapshot - another cool tool!