虚拟机有哪些缺点(虚拟机有什么优点和缺点)

Virtual machines have some disadvantages, including:

Performance loss: the virtual machine needs to be on the upper layer of the host operating system running, which means it will occupy certain system resources and cause performance loss.

Storage space occupation: A virtual machine requires a certain amount of storage space to run, which means it will occupy hard disk space.

High complexity: Virtual machines require installation and configuration, which may be complicated for novices.

Compatibility issues: Sometimes virtual machines cannot fully simulate physical hardware, which may cause compatibility issues.

These shortcomings make virtual machines not always the best choice, especially when high performance is required. However, virtual machines also have some advantages, including isolation and portability. Therefore, whether to use a virtual machine depends on your specific needs and usage scenarios.

In fact, virtual machines are not harmful to computers.

A virtual machine is actually just a piece of software that simulates another computer on one computer. Therefore, if operated correctly, it will not have a bad impact on the system and hardware.

Any work that can be done on a physical computer can be done on a virtual machine. When creating a virtual machine on a computer, you need to use part of the hard disk and memory capacity of the physical machine as the hard disk and memory capacity of the virtual machine. Each virtual machine has an independent CMOS, hard disk and operating system, and the virtual machine can be operated like a physical machine.

Main uses:

1. Demonstration environment. Various demonstration environments can be installed to facilitate making various examples.

2. Ensure the fast operation of the host and reduce unnecessary junk installation programs, occasionally used programs, or testing programs running on the virtual machine.

3. Avoid reinstalling every time. Common tools such as banks are not used frequently and require better confidentiality. They should be run in a separate environment.

4. If you want to test unfamiliar applications, you can install them in the virtual machine and delete them completely.

5. Experience different versions of operating systems, such as Linux, Mac, etc.

Reference for the above content: Baidu Encyclopedia-Virtual Machine

1. Using virtual machines can save costs. Just imagine, if each website uses an independent server, the price of a server is not very low. If you want to build For many websites, the cost of the server is also very high, let alone establishing a personal webmaster and establishing a website group. The cost is not generally high. The use of virtual machines provides great convenience for many small and medium-sized websites

(A virtual host divides a certain amount of disk space on the network server for users to place sites, application components, etc., and provides necessary site functions, data storage and transmission functions. In other words, a server can be divided into many spaces. So as to achieve cost savings) 2. The efficiency of building websites has improved a lot. Using a virtual host will greatly shorten the cycle of building your website. Nowadays, providers are basically electronic. As long as you apply, they can give it to you right away. It is activated. On the contrary, if you use a stand-alone server, you need to install IIS or APACHE, PHP or ASP

NET, system, etc. This requires professional skills and time, which is very troublesome

1. Many functions They are all subject to restrictions. Because hosting companies consider costs, they often impose many restrictions, such as traffic restrictions and IIS restrictions. For some websites that take up a lot of system resources, sometimes they are even shut down directly by the provider. For example, some websites that affect SEO Traffic factors: GZIP compression, keep-alive, etc. all need to be enabled by the provider before you can use them

2. When using a virtual host, the speed is often subject to some restrictions because the provider often puts a The host is sold to many people, so the speed of collecting virtual machines will obviously not be very fast. The website speed will have an adverse impact on website access, user experience, etc.

3. When you build a website, you often You should consider whether the supplier supports a certain function. When purchasing a virtual host, sometimes the functions you need are not exactly what the virtual machine provider can provide, such as some system restrictions, some database restrictions, etc.

4. Some service providers have certain restrictions on website traffic, so that when the website has a large number of visits, it will not be accessible normally

It can be seen that whether the website uses a virtual host or a dedicated server needs to be determined according to the website comprehensive consideration of the situation and expected development

1. Advantages of virtual machines

1. Rapidly implement distributed deployment and increase or decrease at any time.

2. Self-service upgrade configuration, add IP, bandwidth and other functions, no downtime is required during the upgrade process.

3. You can perform self-service soft/hard restart and configure FTP, IIS, etc. with one click.

4. View the running status of resources, traffic, processes, and services in real time.

5. Fully possess the Administrator or Root authority of the host, you can personalize the system, freely install application software and programs, and deploy various Internet applications.

2. Disadvantages of virtual machines

1. Poor independent hardware resources.

2. Poor software support.

3. The hard disk read and write speed is extremely slow.

How virtual machines work

Virtualization technology allows multiple virtual environments to share a system. The hypervisor manages the hardware and separates physical resources from the virtual environment. Resources from the physical environment are partitioned as needed and allocated to virtual machines for use.

When a virtual machine is running, when a user or program issues an instruction that requires more resources from the physical environment, the hypervisor will schedule resource requests from the physical system so that the virtual machine's operating system and applications can access them. Shared physical resource pool.