[Borgbackup] no dedup

[Giuseppe Arvati]

Hello

I'm new to borgbackup and after some tests I'm not able do view 
deduplication. Let me explain. I want to backup a daily VM snapshot into 
a borg repository, now these VM are saved on a NAS and the name is 
something like VM01-xxx.xva where xxx is the day. I created 2 archive in 
the same repository the first with a VM and the second with the same VM 
of the next day. There are no big differences from the to VM. Command 
line: /usr/local/bin/borg create -C lz4 /mnt/vm.borg::traccar-22 
/mnt/xen3/Traccar-22.xva Command line: /usr/local/bin/borg create -C lz4 
/mnt/vm.borg::traccar-23 /mnt/xen3/Traccar-23.xva borg info 
/mnt/vm.borg::traccar-23 Name: traccar-23 Fingerprint: 
627f648409506904f72869b7c2afa0c17ca1730e745f68dd6c303e4d9526804a 
Hostname: apamfs2 Username: root Time (start): Mon, 2017-06-12 15:12:38 
Time (end): Mon, 2017-06-12 15:15:40 Command line: /usr/local/bin/borg 
create -C lz4 /mnt/vm.borg::traccar-23 /mnt/xen3/Traccar-23.xva Number 
of files: 1 Original size Compressed size Deduplicated size This 
archive: 7.45 GB 2.26 GB 2.23 GB All archives: 14.45 GB 4.43 GB 4.40 GB 
Unique chunks Total chunks Chunk index: 5420 5551 As you can see the 
archive traccar-23 is an half of all archive. no dedup

I tried to rename the vm before create the archive, so they have the 
same name/path into the archive,
following FAQ "it always chunks all my files, even unchanged ones"

Using Attic in the same way I had these results ( same 2 files ) Command 
line: /usr/local/bin/attic create --stat /mnt/vm.attic::traccar-23 
/mnt/xen3/Traccar-23.xva Number of files: 1 Original size Compressed 
size Deduplicated size This archive: 7.45 GB 1.78 GB 332.89 MB All 
archives: 14.46 GB 3.50 GB 1.96 GB So what's the problem ? I made the 
tests first with python 3.6.1 self compiled and then with CentOS python 
3.4 Second problem. Borg always show me a warning message about pure 
python msgpack and slow performance I installed msgpack coming with 
CentoOs but nothing What I need to do to ? Thank you very much to all 
guys who want help me. Giuseppe