Necessary folder permissions

[polyfragmented]

Backup and data files are written by the web server (apache/php for you?). Most likely, those processes are running as your ftp user. You should be able to see the user and group numbers in your ftp client. I would say that it's worth making some effort to avoid permissions of 0777.

Yeah, Apache+PHP. As I wrote in the solution above, I have to use the CGI/FTP user "workaround" in order to avoid using CHMOD 777 on editable files. If I don't use it, I can't edit files from the backend.

GS is not the only system which bumps into this obstacle with all-inkl, e.g. Contao CMS provides a special mode which edits/uploads files as the FTP user.

You're right, using 777 should be avoided, yet GS' install routine suggests it for /backup/ and /data/ if the needed folders aren't writable. Have you CHMODed those folders differently?