Cloud storage is a model of computer data storage in which the digital data is stored in logical pools, said to be on "the cloud".
The physical storage spans multiple servers (sometimes in multiple locations), and the physical environment is typically owned and managed by a hosting company.
These cloud storage providers are responsible for keeping the data available and accessible, and the physical environment secured, protected, and running.
People and organizations buy or lease storage capacity from the providers to store user, organization, or application data.
Cloud storage services may be accessed through a cloud computing service, a web service application programming interface (API) or by applications that use the API.
Cloud storage is based on highly virtualized infrastructure and is like broader cloud computing in terms of interfaces, near-instant elasticity and scalability, multi-tenancy, and metered resources.
Cloud storage services can be used from an off-premises service (Amazon S3) or deployed on-premises .
There are three types of cloud storage: a hosted object storage service, file storage, and block storage. Each of these cloud storage types offer their own unique advantages.
Examples of object storage services that can be hosted and deployed with cloud storage characteristics include Amazon S3, Oracle Cloud Storage and Microsoft Azure Storage, and distributed storage research projects like Ocean Store and VISION Cloud.
Examples of file storage services include Amazon Elastic File System (EFS) and Qumulo Core,[8] used for applications that need access to shared files and require a file system.
This storage is often supported with a Network Attached Storage (NAS) server, used for large content repositories, development environments, media stores, or user home directories.
A block storage service like Amazon Elastic Block Store (EBS) is used for other enterprise applications like databases and often require dedicated, low latency storage for each host.
This is comparable in certain respects to direct attached storage (DAS) or a storage area network (SAN).
Made up of many distributed resources, but still acts as one, either in a federated[9] or a cooperative storage cloud architecture
Highly fault tolerant through redundancy and distribution of data
Highly durable through the creation of versioned copies
Typically eventually consistent with regard to data replicas.
Companies need only pay for the storage they actually use, typically an average of consumption during a month, quarter, or year.
This does not mean that cloud storage is less expensive, only that it incurs operating expenses rather than capital expenses.
Businesses using cloud storage can cut their energy consumption by up to 70% making them a more green business.
Storage maintenance tasks, such as purchasing additional storage capacity, are offloaded to the responsibility of a service provider.
Cloud storage provides users with immediate access to a broad range of resources and applications hosted in the infrastructure of another organization via a web service interface.
Cloud storage can be used for copying virtual machine images from the cloud to on-premises locations or to import a virtual machine image from an on-premises location to the cloud image library.
In addition, cloud storage can be used to move virtual machine images between user accounts or between data centers.
loud storage can be used as natural disaster proof backup, as normally there are 2 or 3 different backup servers located in different places around the globe.
