Use the database backup feature (System -> Database -> Manage Backups), first make a Backup and then save it locally. On the next installation you can get back all your data online simply restoring that file.
If you are not going to reinstall with a newer version you could perform a "Tarball backup" and restore the entire website instead.
Lanius CMS installation 
![[up]](components/faq/images/up.png)