Hi Igor,
When you compress files, a single different byte changes the whole content
of the compressed file. That's why the deduplication it's not working,
because all the blocks of all the compressed files you ever uploaded to
tarsnap are different to each other.
If you have to upload your files compressed, try gzip --rsyncable, it makes
your compressed files work better with rsync and also with tarsnap.
Hope it helps.
--
Mauro Ciancio

On Tue, Jan 19, 2016 at 6:12 AM, Igor Ostapenko <[email protected]>
wrote:

> Hi,
>
>
>
> Could you please give me a clue what's wrong in the following situation.
>
>
>
> I have a directory with static content. Subsequent tarsnapping looks to
>
> be without deduplication, like content was changed (but it's not). I've
>
> taken one of its files for testing:
>
>
>
> $ # The first run
>
> $ tarsnap -cvf .test.daily.20160119104958 .test
>
> a .test
>
> a .test/file.tar.xz
>
>                                        Total size  Compressed size
>
> All archives                               8.3 GB           3.5 GB
>
>   (unique data)                            1.4 GB           622 MB
>
> This archive                                10 MB            10 MB
>
> New data                                    10 MB            10 MB
>
>
>
> $ # The second run
>
> $ tarsnap -cvf .test.daily.20160119105034 .test
>
> a .test
>
> a .test/file.tar.xz
>
>                                        Total size  Compressed size
>
> All archives                               8.3 GB           3.5 GB
>
>   (unique data)                            1.4 GB           622 MB
>
> This archive                                10 MB            10 MB
>
> New data                                    10 MB            10 MB
>
>
>
> $ ls -nl .test
>
> total 10580
>
> -rw-------  1 501  20  10830836 19 Jan 10:49 file.tar.xz
>
>
>
> $ tarsnap --version
>
> tarsnap 1.0.36.1
>
>
>
>
>
> I have a bunch of *.gpg files in another archive where deduplication
>
> works as expected.
>
>
>
> It's a need to keep files in tar.xz. Anyway, conceptually I expected
>
> deduplication in this case.
>
>
>
>
>
> What do you think?
>

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