Hi,
Bw 7.x on wards back up data was not required.
While doing repartition it self system will take up back data into Shadow tables which starts with /BIC/4*.. Once repartition was over, automatically back up data will move to E and F fact tables and shadow tables data will be deleted automatically.
You can cross check shadow tables have data or not after the repartition at SE11, use above name.
Please refer this note 1008833.
Thanks