cloud computing is the increase, use, and delivery model of Internet-based related services, usually involving the provision of dynamically scalable and often virtualized resources over the Internet。The cloud is a metaphor for the network, the Internet。In the past, the telecommunications network was often represented by the cloud in the diagram, and later it was also used to represent the abstraction of the Internet and the underlying infrastructure。As a result, cloud computing can even allow you to experience 10 trillion calculations per second, which is so powerful that you can simulate nuclear explosions, predict climate change, and market trends。Users access the data center through computers, laptops, mobile phones, etc., and perform calculations according to their own needs

There are several definitions of cloud computing。Can there be at least 100 explanations for what cloud computing is。At this stage, it is widely accepted that the National Institute of Standards and Technology (NIST)定义：Cloud computing is a pay-as-you-go model，This model provides usable, convenient, on-demand network access，Enter the configurable computing resource sharing pool (resources include networks)，Server，存储，Application software，服务），These resources can be provided quickly，It requires very little administrative effort，Or very little interaction with the service provider。

By making computing distributed across a large number of distributed computers, rather than on-premises computers or remote servers, enterprise data centers will operate more like the Internet。This enables enterprises to switch resources to the applications they need, accessing computers and storage systems on demand。

cloud storage is a new concept that extends and develops from the concept of cloud computing，It refers to functions such as clustering applications, grid technology or distributed file systems，A large number of different types of storage devices on the network work together through application software，A system that jointly provides external data storage and service access functions。When the core of the computing and processing of the cloud computing system is the storage and management of a large amount of data, a large number of storage devices need to be configured in the cloud computing system, then the cloud computing system will become a cloud storage system, so the cloud storage is a cloud computing system with data storage and management as the core。

From a technical point of view, the relationship between big data and cloud computing is as inseparable as the two sides of the same coin。Big data cannot necessarily be processed by a single computer, and must adopt a distributed computing architecture。It is characterized by the mining of massive data, but it must rely on the distributed processing, distributed database, cloud storage and virtualization technology of cloud computing。

Cloud computing can be considered to include several levels of services: Infrastructure as a Service (IaaS), Platform as a Service (PaaS), and Software as a Service (SaaS).。

IaaS: Infrastructure as a service

IaaS: Infrastructure-as-a-Service (IAaS)。Through the Internet, consumers can obtain services from a well-established computer infrastructure。For example, rent a hardware server。

PaaS: Platform as a Service

PaaS(platform-as-a-service) : Platform as a Service。PaaS actually refers to the software development platform as a service, in the SaaS model to submit to users。Therefore, PaaS is also an application of the SaaS model。However, the emergence of PaaS can accelerate the development of SaaS, especially the speed of SaaS application development。For example: software personalized custom development。

SaaS: Software as a service

Software-as-a-service (SaaS) : Software as a Service。It is a model of providing software over the Internet, and users do not need to buy software, but rent Web-based software from a provider to manage business activities。For example, Sunshine Cloud server。