Cloud storage

Cloud storage is a model for storing computer data in remote, logical pools. Instead of keeping files on a local hard drive, users access them over a network, which is usually the Internet. This system relies on a physical infrastructure that spans many different servers. These servers might even be located in several different geographic areas. A cloud computing provider typically owns and manages this entire physical environment. They are responsible for making sure the data stays accessible and the hardware remains secure and operational.

The underlying mechanism of cloud storage relies on highly virtualized infrastructure. This means the physical hardware is divided into many virtual parts that act as single resources. The system offers near-instant elasticity, which allows it to grow or shrink based on demand. It also features multi-tenancy, where many different users share the same physical resources. Because resources are metered, users often only pay for the specific amount of storage they actually consume. This can turn what would be large capital expenses into smaller, ongoing operating expenses.

There are three distinct types of cloud storage architecture. The first is hosted object storage, which is used for a wide variety of data types. Examples include Amazon S3, Microsoft Azure Storage, and Oracle Cloud Storage. The second type is file storage, which is used when applications need to access shared files through a file system. This is often supported by a Network Attached Storage, or NAS, server. The third type is block storage, such as Amazon Elastic Block Store (EBS). Block storage is used for enterprise applications like databases because it provides dedicated, low latency storage.

The history of these ideas stretches back several decades. J. C. R. Licklider is believed to have invented the concept of cloud computing in the 1960s. He worked on ARPANET to help connect people and data from any location at any time. In 1983, CompuServe began offering users a small amount of disk space for file uploads. By 1994, AT&T launched PersonaLink Services, which used the term "the cloud" in its commercials. Amazon Web Services later introduced Amazon S3 in 2006. This service helped popularize the technology for companies like Dropbox and Pinterest.

Today, a few massive companies dominate the global cloud services market. As of 2024, Gartner ranked the top platforms as AWS, Google, Microsoft, Oracle, Alibaba, IBM, Huawei, and Tencent. Together, these providers account for 97% of the entire global market. The market shares vary significantly by region. In the United States, AWS is dominant with a share between 31% and 50%. In China, Alibaba Cloud is a major leader. In 2023, Alibaba Cloud ran 80% of China's technology companies and half of all AI LLM companies.

Cloud storage offers several significant advantages for modern organizations. It can act as a natural disaster proof backup because data is often replicated across two or three different servers globally. This distribution makes the system highly fault tolerant and durable. Businesses can even reduce their energy consumption by up to 70% by using these services. Additionally, cloud storage allows for easy movement of virtual machine images between different user accounts or data centers. It can also function as a central file server for organizations that have many different office locations.

However, using the cloud also introduces specific security and performance concerns. Because data is stored in a shared environment, it can increase the "attack surface" for hackers. There is also a risk regarding the physical disposal of old equipment or the reallocation of storage space. To protect sensitive information, users often employ encryption. Encryption in transit protects data while it travels over a wide area network (WAN). Encryption at rest protects the data while it sits on the provider's hardware. Users can also choose a private cloud or use on-premises gateways to keep encryption keys under their own control.