A method for data protection includes, in a first operational mode, sending data items for storage in a primary storage device and in a secondary storage device, while temporarily caching the data items in a disaster-proof storage unit and subsequently deleting the data items from the disaster-proof storage unit, wherein each data item is deleted from the disaster-proof storage unit upon successful storage of the data item in the secondary storage device.An indication of a fault related to storage of the data in the secondary storage device is received. Responsively to the indication, operation is switched to a second operational mode in which the data items are sent for storage at least in the primary storage device and are cached and retained in the disaster-proof storage unit irrespective of the successful storage of the data items in the secondary storage device.