**3.2 Cloud computing storage**

Cloud storage provides companies with greener computing services. Cloud computing storage cuts companies' and organizations' energy consumption and computing expenses. By using cloud storage, purchasing additional storage capacity is minimized and storage maintenance tasks and expenses are reduced. Cloud storage is a service package in which data is stored, managed, backed up remotely, and made available to users over a network and internet services. Cloud storage is based on a virtualized infrastructure with accessible interfaces. Cloud-based data is stored in servers located in data centers managed by a cloud provider. A file and its associated metadata are stored in the server by using an object storage protocol. The server assigns an identification number, ID, to each stored file. When the file needs to be retrieved, the user presents the ID to the system, and the content is assembled with all its metadata, authentication, and security. The most common use of cloud services is cloud backup, disaster recovery, and archiving of infrequently accessed data. Cloud storage providers are responsible for keeping the data available and accessible and the physical environment protected and running. People and organizations buy or lease storage capacity from the providers to store and archive data files. Cloud storage services may be accessed via cloud computers and web services that use application programming interfaces, API, such as cloud desktop storage and cloud storage gateways. There are three main cloud-based storage architecture models public, private, and hybrid.
