snapshot file size

I found this post: https://community.vertica.com/vertica/topics/full_and_incremental_backups_issue_using_vbr_py_on_vertica_6_1_2

and by following it I used the command "du -sh *"
which returns the following output:

In the original backupDir:
180G    full_vertica
50G    full_vertica_archive20130925_211505
50G    full_vertica_archive20130926_211504

In another directory
178G    full_vertica
178G    full_vertica_archive20130925_211505
179G    full_vertica_archive20130926_211504

and I still don't get why I find these dimensions on the destination directory.

Could it be because each snapshot has pointers to "old data" in addition to incremental data and when I copy each snapshot I am copying also the "old data" through those pointers?

In this case, If I want to store a snapshot in another directory, do I have to copy also the previous snapshots or only the one I am interested in?

thanks,
Pietro

by using "du -sh -l *" on the original backupDir I can force to follow simbolic links in the incremental backup, and I find:

180G    full_vertica
178G    full_vertica_archive20130925_211505
179G    full_vertica_archive20130926_211504

So now I understand that a copy of this directories, which recursively follows links, is 180GB x 3 instead of 180GB + 50GB x 2.

I need to know only if I can just copy (recursively) the only snapshot I need to have a full and consistent snapshot.