dumpBackup.php do not sort the entries and there is no option to do it as far as I know.
I'm using importDump.php and looking at http://localhost:8080/mediawiki/Special:AllPages to govern the upload process, but its only useful to estimate the quantity that has been uploaded. I cannot verify that all articles that begins with "A", "B", and "C" for example has been uploaded.
I suggest that you add option --sort used to sort by namespace. Example --sort=namespace:0