What is a public cloud?
Public cloud: refers to the third-party provider to provide users with a cloud that can be used; public cloud can generally be used through the Internet, which may be free or low-cost, and the core attribute of the public cloud is shared resource service;
Using cloud service resources is as convenient and efficient as using water, electricity, gas and other resources. Instead of purchasing hardware devices in advance, you can create as many resources as you need, depending on your business needs. In the process of using, as the service expands, you can expand the disk and increase the bandwidth at any time. If you no longer need it, you can free up resources and save money.

Public cloud vs. traditional IDC


Business migration
Migration tool
The Qianyun tool is a cloud-moving service client that supports online migration of physical machine servers, virtual machines, and other cloud platform cloud hosts to cloud servers. The Yunyun tool belongs to the P2V or V2V use category. P2V (Physical to virtual) represents migration from a physical IDC environment to a cloud server. V2V (Virtual to virtual) represents migration from a virtual machine environment or a cloud platform host to a cloud server.
Migration method

File-level migration: source host data, migrated by file
Mirror level migration: source host data, migrated in blocks
Online migration: source host business, normal operation
Offline migration: source host business and operating system, not running
P2V (physical server migration to cloud server)
V2V (virtual host/other cloud platform server migration to cloud server)
Migration diagram

Application scenario
Corporate website or lightweight web application
The initial stage of the website has a small amount of access, and only a low-profile cloud server is required to run applications, databases, storage files, and so on. With the development of the website and the business, the configuration of the cloud server can be upgraded at any time, or the number of cloud servers can be increased, and there is no need to worry about the inconvenience of resources caused by the low-computing computing unit in the sudden increase of business.
Multimedia and high-concurrency apps or websites
The cloud server is paired with the object storage OSS, which stores static images, videos, or downloads to reduce storage costs. Together with CDN and load-balancing SLB, you can significantly reduce user access latency, reduce network bandwidth costs, and increase availability.
High I/O database
Support for databases that host high I/O requirements. Use a higher-configured I/O-optimized cloud server with an SSD cloud disk for high I/O concurrent response and higher data reliability. You can also use multiple I/O-optimized cloud servers with a medium-lower configuration to work with load balancing to build a highly available infrastructure.
Apps or websites with fluctuating traffic
Some applications, such as grabbing red envelopes, coupon-issuing apps, e-commerce sites, and ticketing sites, can experience huge fluctuations in a short period of time. Elastic scaling can be used together to automate cloud servers before request spikes and reduce the number of cloud servers as they enter the request trough. Meet the resource requirements when the traffic reaches its peak, while reducing costs. If you are paired with load balancing, you can also implement a highly available architecture.
Public cloud brand
