A cloud storage appliance is a stand-alone computing device or virtual machine (VM) image used to move data from a local site to a remote cloud storage service provider. Such appliances are used for primary, backup and archive data.
An appliance can be a proprietary vendor server with pre-installed software or a virtual appliance that can be installed on ordinary commodity hardware. A cloud storage appliance often includes an on-premise cache that facilitates a tiered storage approach, allowing quick access to the most active or most recent data from the local system instead of the cloud.
Appliances also use data deduplication and compression to use available bandwidth efficiently and move data as quickly as possible. Reducing the data footprint also lowers cost because cloud providers charge for over-the-wire transfers as well as the amount of storage space used.