The capacity of an HPE StoreOnce 3620 can be expanded by adding disk enclosures. This method allows the system to scale its storage capacity by adding additional disk shelves to the existing configuration, providing more storage space for backups. The StoreOnce 3620 is designed to support this expansion, enabling businesses to meet growing data protection needs without replacing the entire system. For more information, refer to: HPE StoreOnce 3620 Documentation