The backup is stored on local disk first so it can be captured at high speed. Later on, backup software or a cloud storage appliance is used to encrypt and transmit the data to the cloud service provider. After the backup has been transferred to the cloud, the first-in backup data on the local disk may be discarded to make room for the next backup. The last-in backup is retained in case it is needed for quick data recovery.
See also: FIFO