For example;
1) I create a file named test1.txt
1b) with the content 123456789 reapeted over and over again for 10 times
2) Will this file be de-duplicated?
3) I open the file named test1.txt
3b) and insert a “0” as the first letter in the file, and save the file as test2.txt
4) Will this file be uniq, or will the dedup find duplicates here?

Some vendors; such as EMC (DataDomain) mentioned “variable-block-size”
And TSM uses same technology.
Is this used in Lessfs too?

And is ther example of reduction ratio for this filesystem?

THanks in advance
Regards Tomas

Johnathan – did you find any workaround?

Nick

Following is result:

[root@localhost mta]# mklessfs /etc/lessfs.cfg
[root@localhost mta]# /usr/bin/lessfs start
Starting lessfs: Usage: /usr/bin/lessfs {start|stop|restart}

mklessfs /etc/lessfs.cfg /dev/sdb1
[root@localhost mta]# /usr/bin/lessfs start
Starting lessfs: Usage: /usr/bin/lessfs {start|stop|restart}

[root@localhost init.d]# cd /etc/init.d
[root@localhost init.d]# ./lessfs start
Starting lessfs: Usage: /usr/bin/lessfs {start|stop|restart}

[root@localhost init.d]# ./lessfs restart
Stopping lessfs: umount: /fuse: not mounted

Starting lessfs: Usage: /usr/bin/lessfs {start|stop|restart}

[root@localhost init.d]# mkfs -t lessfs /dev/sdb1
mkfs.lessfs: No such file or directory
[root@localhost init.d]# mkfs.ext3 -t lessfs /dev/sdb1
mke2fs 1.40.2 (12-Jul-2007)
mkfs.ext3: invalid blocks count – /dev/sdb1
[root@localhost init.d]#

How can I do now

What can I do now?
Thank u

“The kernel used is to old for larger then 4k blocksizes, kernel >= 2.6.26 is required”

Is there anything I can do to bypass this error?

Thanks.
Johnathan.

Thanks,
-Pete

1. To use LessFS you need Linux with recent kernel >=2.6.27(?) and FUSE package >= 2.8.0. You’ll need to download, compile & install tokyocabinet package (using compile time option –enable-off64 to have ability to create filesystems > 2GB on 32-bit architectures). Then you compile & install lessfs.

2. After installing take a look on files in etc/ subdirectory in lessfs source package. It contains two files: lessfs.cfg (with some example configuration) and lessfs – standard SystemV init start/stop/restart script. Revise them and put in /etc and /etc/init.d directories accordingly. If you are running Slackware, you may wish to name the latter rc.lessfs and put into /etc/rc.d directory.

3. When you are done with config, it’s time to format (mkfs) your new lessfs filesystem. Just invoke `mklessfs /etc/lessfs.cfg’ to create empty lessfs. Just after creation, tokyocabinet database files (which is lessfs’ backend) will take about ~150 MB of space when using default settings, and of course will grow in time.

4. Mount it, using `/etc/init.d/lessfs start’ or similar command.

LessFS Tuning.

1. Read “README.performance_or_suffer” file from source package.

2. Use maximum block size with lessfs. There is no real reason for using blocksize smaller than 128k, especially since 1.1.0-beta4. The bigger the blocksize, the less metadata is needed to describe it. Compression is more efficient with bigger blocks, metadata files grow slower, memory requirements are milder etc. In practice, smaller blocks does not impose better deduplication.

3. LessFS and virtualization: When storing loop-based virtual disks images on lessfs, use the same block/cluster size on guest filesystems and lessfs. I.e. use 64k block size on lessfs and 64k clusters on guest NTFS and make sure that your partitions are properly aligned, so guest fs’ blocks/clusters fill host fs’ blocks. Avoid defragmentation of guest volumes as it leads to host fs fragmentation

4. Play with *_BS settings from lessfs.cfg config file and post some information on results, please. Or maybe someone could share his/her experience on this subject here?