[Borgbackup] question about deduplicated size stats

[Maurice Libes]

Le 13/09/2017 à 15:26, Chris Downing a écrit :
> Just jumping in here - not much experience with Borg but I think I 
> understand the query...
>
> It sounds like what Maurice is after is a way to answer: "If all 
> archives except this one were not present, what would be the 
> deduplicated size of this archive?"
sorry, I dont know if this was I wanted to say :-)

I just wanted to see somewhere in the stats (elsewhere than in the log 
file) the informations of the
deduplicated size that "/borg create"/ displays after an archive backup;

i.e the volume of new fragments found at time "t" for one particular 
archive at the moment where it is done


but I am sensible to this argument of john:
/>It can be confusing that they differ, but as it stands it reflects how 
much space would be freed if you deleted >that one archive.

/what is confusing for me is that , it is the same name deduplicated 
size, but not computed in the same manner
between "borg create" and "borg info/"
/
/
/
let's say If I want to show the benefit of borg deduplication day after 
day , it would of some interest
to display somewhere the B dedup volume for archive2 and the C dedup 
volume for archive3

A     -> archive1
A B   -> archive2
A B C -> archive3


dont know if it is a point of interest, It's up to you
maybe explain this somewhere in the documentation? or in the man file

(now I know I have to check what I search in the log file)

thanks for the thread
M//
/
=========
/time of "/_borg create_/" (extracted from log file)

Archive name: bioinfo-2017-09-07/** Original size Compressed size Deduplicated size This archive: 6.44 TB 
4.02 TB *2.44 GB* All archives: 65.05 TB 41.60 TB 3.96 TB**/


time of "_/borg info/_" some weeks later

Name: bioinfo-2017-09-07
                        Original size      Compressed size    Deduplicated size

This archive:                6.44 TB              4.02 TB/*110.13 MB*/
All archives:               66.26 TB             41.89 TB              4.29 TB

>
> If correct, I agree that it would be a useful data point, but have no 
> idea how complex it would be to generate that information (assuming it 
> doesn't already exist somewhere).
>
> On Wed, 13 Sep 2017 at 14:09 John McCabe-Dansted <gmatht at gmail.com 
> <mailto:gmatht at gmail.com>> wrote:
>
>         After a great reflexion :-)  this is very confusing for my
>         mind (and some friends) because we expected to find
>         the deduplicated size information as returned by the/*borg
>         create*/ command at the time the backup was made
>
>         that is to say the deduplicated size of one archive at the
>         time it is made
>         which is to my opinion more interesting to see the benefit of
>         deduplication
>
>
>
>     It can be confusing that they differ, but as it stands it reflects
>     how much space would be freed if you deleted that one archive.
>
>     I think that the easiest way if you want the the original value of
>     the "Deduplicated size" is to log the output of borgbackup.
>
>     I guess the other statistic that would be of interest is how much
>     space would be freed if some set of archives were deleted.
>
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>

-- 
M. LIBES
Service Informatique OSU Pytheas - UMS 3470 CNRS
Batiment Oceanomed
Campus de Luminy
13288 Marseille cedex 9
Tel: 04860 90529

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