Hey Al-Rifaie,
you need to free up space. The fastest way is to delete a Catalyst store, CIFS/NFS share or VTL on the device and recreate them. This takes seconds, but may require full sync during next replication. Or you could expired objects and delete unprotected slots. Make sure the housekeeping on the StoreOnce has enough time to clean up. This will take time (days, weeks).
Regards,
Sebastian Koehler