Hi,
I’m a newbie with duplicati…
I have a difference between number of versions and number of backup files.
Example : 2 versions in GUI but 1 backup file on my server
And, i tried to purge/delete files to restart on a good footing but, even if the files were deleted, the GUI still tells me that I have X backup versions.
Thx for your help
Welcome to the forum @Alandil
What do you mean by “backup file”? Duplicati makes files on the destination with “dblock” and “dindex” in their name. Their count depends on the amount of data (default size limit is 50 MB). There is one “dlist” file upload at the end of backup. The count should match the version count. Look at the Restore dropdown for most reliable count if you’re doing things other than backups.
A successful initial backup typically makes at least 3 files, one each of dblock, dindex, and dlist.
If you mean the Duplicati command of those names, purge affects files not versions, and delete doesn’t update the home screen statistics, but you can view the Restore menu to view versions.
[If you mean the Duplicati command of those names, purge affects files not versions, and delete doesn’t update the home screen statistics, but you can view the Restore menu to view versions [/quote]
Thx for your answer 
That comment helped me understand 
I couldn’t see why I only had files for 1 version but Duplicati told me it had 2 in the GUI. If the GUI doesn’t base itself on the state of the files to say how many versions are available, then that’s normal
Thanks again.
You’re still not saying what you’re seeing. Can you describe in terms of dblock, dindex, dlist?
After a backup, both the home screen and Restore list should match the number of dlist files.
i don’t know how to describe. I counted the files for 1 version and made a second backup then deleted version 1.
While I’d prefer a breakdown by file name, was there only 1 file in total? Should be at least 3.
Will probably add at least 3 more files (at least 1 dblock, 1 dindex, 1 dlist, just like the original).
Will delete 1 dlist and maybe some dblock and dindex if compact runs. Will update the Restore view but probably not home page versions count.
While dlist files are related to versions, dblock and dindex files are not, as unchanged data isn’t uploaded again. Instead, data in older dblock files is referenced again, as being in new backup.
Incremental backups
Duplicati performs a full backup initially. Afterwards, Duplicati updates the initial backup by adding the changed data only. That means, if only tiny parts of a huge file have changed, only those tiny parts are added to the backup. This saves time and space and the backup size usually grows slowly.
Deduplication
Duplicati analyzes the content of the files and stores data blocks. Due to that, Duplicati will find duplicate files and similar content and store them only once in the backup. As Duplicati analyzes the content of files it can handle situations very well if files and folders are moved or renamed. As the content does not change, the next backup will be tiny.