Proxmox 2.3 & vzdump too big

[tsaenger]

Hi,
i am using Proxmox 2.3 with Ubuntu 10 LTS as guest.
I configured a backup-Job (snapshot LZO). I works fine, but i am wondering why the backup-file is so big.

[TABLE]
[TR]
[TD]VMID
[/TD]
[TD]NAME
[/TD]
[TD]STATUS
[/TD]
[TD]TIME
[/TD]
[TD]SIZE
[/TD]
[TD]FILENAME
[/TD]
[/TR]
[TR]
[TD]100
[/TD]
[TD]primux
[/TD]
[TD]OK
[/TD]
[TD]01:19:54
[/TD]
[TD]50.78GB
[/TD]
[TD]/mnt/proxmox_save/dump/vzdump-qemu-100-2013_08_16-03_00_02.vma.lzo
[/TD]
[/TR]
[TR]
[TD="colspan: 3"]TOTAL
[/TD]
[TD]01:19:54
[/TD]
[TD]50.78GB
[/TD]
[TD][/TD]
[/TR]
[/TABLE]

If i check the guest-System i get following Disk-Usage:

# df / -H
Dateisystem             GröÃe   Benut  Verf Ben% Eingehängt auf
/dev/vda1              155G    17G   131G  12% /


# df -H
Dateisystem             GröÃe   Benut  Verf Ben% Eingehängt auf
/dev/vda1              155G    17G   131G  12% /
none                   2,1G   181k   2,1G   1% /dev
none                   2,1G      0   2,1G   0% /dev/shm
none                   2,1G   472k   2,1G   1% /var/run
none                   2,1G      0   2,1G   0% /var/lock
none                   2,1G      0   2,1G   0% /lib/init/rw
none                   155G    17G   131G  12% /var/lib/ureadahead/debugfs

Does someone has an idea, what i have to do to get a smaler backup-File?

Thanks

Tobias