Is a bare metal server a physical machine? What is the difference between it and a virtual machine? Bare metal servers have complete processor characteristics at the physical machine level. Bare metal servers have the advantages of physical machine-level resource isolation, which is particularly suitable for cloud deployment of traditional non-virtualized scenarios. In the face of some complex scenarios and applications, bare metal servers have stronger performance than cloud hosts; higher CPU, memory, and bandwidth performance. So, why is it said that bare metal servers have the advantages of both physical machines and cloud hosts? What is the difference between it and a virtual server?
　　I have always thought that bare metal servers are physical machines. In recent days, I have discovered that bare metal servers are not physical machines, but a kind of virtualization technology with independent resources. For example, the more common ones we have are Shenlong bare metal servers and Blackstone physical servers. They are the same products. They just go directly to the hardware layer and can be directly operated at the hardware level.
　　1. Why do bare metal servers have the advantages of physical machines?
　　Elastic bare metal servers, with the word elastic added. The introduction is as follows. Elastic bare metal servers (ECS Bare Metal Instance) are new computing server products built based on the next-generation virtualization technology that is completely independently developed. They have both the elasticity of virtual machines and the performance and functional characteristics of physical machines. Compared with the previous generation of virtualization technology, the next generation of virtualization technology not only retains the elastic experience of ordinary cloud servers, but also retains the performance and characteristics of physical machines, and fully supports nested virtualization technology. How to see it:
　　1. Look at the specification configuration: Bare metal servers have complete processor characteristics at the physical machine level. Bare metal servers provide instance types suitable for different business scenarios, including general purpose, local storage, memory optimization, IO optimization, etc. Different types of instances have different configurations in terms of CPU, memory capacity, storage media, storage capacity, network card number, etc.
　　2. Look at the storage configuration: In the face of some complex scenarios and applications, bare metal servers have stronger performance than cloud hosts; higher CPU, memory, and bandwidth performance. Different types of bare metal servers have different media, different interfaces, and different local disk capacities. If your business requires data redundancy, it is recommended that you purchase a pure metal server with a raid card. For bare metal servers without local disks, it supports booting from cloud hard disks to achieve minute-level distribution (called fast delivery bare metal servers).

　　3. Look at the network configuration: Bare metal servers support virtual private clouds (VPC), insist on interconnection with cloud servers, GPU cloud servers and other cloud products, and provide more than 2Gb/s of intranet bandwidth. Support high-speed networks, provide unlimited bandwidth between bare metal servers in the same availability zone, and the intranet bandwidth can reach more than 10gb/s. VLAN supports custom networks, and QinQ users of network isolation technology physically provide additional physical planes and network bandwidth. Support IB networks, whose low-latency and high-bandwidth network characteristics can be used in many high-performance computing (HPC) projects. 4. Look at the image configuration: The resource isolation advantage of bare metal servers at the physical machine level is particularly suitable for cloud deployment of traditional non-virtualized scenarios. Public, private and shared images can be used. 5. Look at the security configuration: All data and applications on bare metal servers are completely privatized; the same as traditional server rental and server hosting. Bare metal servers maintain the same security group policy as cloud servers. Support enterprise host security services (Host Security Service, HSS) to improve the overall security of the server. Supports Anti-DDoS traffic cleaning service, providing DDoS attack protection and real-time attack alarm notification at the network layer and application layer. Supports Web Application Firewall (WAF) to protect the security and stability of Web services.
　　Compared with physical servers, bare metal servers can be as simple as managing cloud hosts. Through the panel, you can restart bare metal servers, reinstall bare metal servers, handle common faults of bare metal servers, and monitor traffic bandwidth of bare metal servers with one click. And it has the same high cost-effectiveness as cloud servers. Bare metal servers are combined with fully automated management methods, just like cloud servers, which effectively reduces technical operation and maintenance costs.
　　Compared with cloud servers, elastic bare metal servers have super strong and stable computing power. Through the self-developed virtualization 2.0 technology, your business applications can directly access the processor and memory of the elastic bare metal server without any virtualization overhead. Elastic bare metal servers have complete processor characteristics at the physical machine level (such as Intel VT-x) and the resource isolation advantages at the physical machine level. They are particularly suitable for cloud deployment of applications in traditional non-virtualized scenarios.
　　2. Look at the applicable scenarios of bare metal servers: Elastic bare metal servers realize customer value through technological innovation. Specifically, the advantages of elastic bare metal servers make them mainly used in products with exclusive computing resources for users. For example, it can enable games and financial businesses to obtain better performance and faster response. In addition, in terms of security, it has physical isolation and chip-level trusted execution environment, which can ensure that encrypted data can only be calculated in a secure and trusted environment. In addition, it is compatible with a variety of proprietary clouds and heterogeneous instruction set processors, and bare metal servers are suitable for the following four types of application services. 1) User-exclusive computing resource products: websites and applications with high security and regulatory requirements such as financial securities. 2) Encrypted computing: high-performance applications such as supercomputing centers, gene sequencing, and big data analysis. 3) Compatible with a variety of proprietary clouds: building core databases, scenarios that require exclusive resources and network isolation. 4) Heterogeneous instruction set processor support: deploying one-stop mobile applications such as mobile games and mobile apps. However, it is also important to note that the shortcomings of elastic bare metal servers are: they do not support specification changes. When a hardware failure occurs in an elastic bare metal server, failover is supported and all data is retained in the cloud disk.
　　From the above two points, it can be seen that a bare metal server is a physical machine or a cloud host. In fact, it can be summarized in one sentence, called a bare metal server, which has the advantages of virtual machine elasticity and physical machine performance. So what exactly is this thing? If you have any needs, you can consult JTTI