A cloud storage gateway is a hardware- or software-based appliance located on the customer premises that serves as a bridge between local applications and remote cloud-based storage. A cloud storage gateway provides basic protocol translation and simple connectivity to allow the incompatible technologies to communicate transparently.

The gateway may be a stand-alone computing device or a virtual machine (VM) image that provides basic protocol translation and connectivity that allows incompatible technologies to communicate transparently.

The need for a bridge between cloud storage systems and enterprise applications arose because of an incompatibility between the protocols used for public cloud technologies and legacy storage systems.

Most public cloud providers rely on Internet protocols, usually a RESTful API over HTTP, rather than conventional storage area network (SAN) or network-attached storage (NAS) protocols.

Many of today's cloud storage gateway products provide data de-duplication and compression capabilities to make use of available bandwidth efficiently and move data as quickly as possible. A cloud storage gateway is also known as a cloud storage controller or cloud storage appliance.

A cloud storage gateway is designed to provide interoperability between different data protocols used in a client/server cloud architecture. It allows interoperability between the application programming interface (API) of a client's REST/SOAP-based data storage and Internet SCSI (iSCSI), Fiber Channel (FC).

Generally, cloud storage gateways are implemented as software gateways that provide a suite of services to facilitate seamless data transfer and retrieval between remote cloud storage servers, data compression for faster transfer, version management and control of entire storage snapshots and run-time encryption, which ensures secure data transmission.

Key features include:

• scheduled local & cloud backup

• Selective file backup

• Bandwidth optimized cloud backup with block-level de-duplication

• Supports Windows, Linux and Mac.