What is load balancing? How does DNS achieve load balancing?

When configuring domain name resolution , We can point one domain name to multiple IP Do you ？ The answer is yes , This is also what we passed DNS Common practices for load balancing .

One 、 What is load balancing ？

Some large videos 、 Game website or application , We are facing huge traffic all the time , A single server simply cannot meet normal access requests . So we need to equip multiple servers , Allocate traffic to reduce server pressure , Ensure business continuity , This is what we often call load balancing .

Two 、DNS How to realize load balancing ？

There are many ways to achieve load balancing , among DNS It is a very simple and effective technical means .

The principle is that we set multiple for the same domain name A Record , Point to different IP Address . When a user accesses ,DNS The server will return different information for the user according to the weight or geographical location IP. In this way, the allocation of access traffic is realized , It not only reduces the load pressure of a single server , It also improves the access speed of users .

Illustrate with examples , Beijing users visit the official websites of China and Kuwait （www.sfn.cn）,DNS It will return according to the user address IP Address 1, Users in Shanghai visit the official websites of China and Kuwait ,DNS Returns a different IP Address 2, Among them, the judgment standard is the one with the least number of routes IP Address as the result of return .

3、 ... and 、DNS Advantages of load balancing

adopt DNS Load balancing , It saves the trouble of website management and maintenance load server , At the same time, it is more flexible in technology , The management of load balancing can be realized only by increasing or decreasing the parsing records . At the same time, many DNS（ Such as those of China and Kuwait Cloud analysis ） It also supports domain name resolution based on geographical location , This will resolve the domain name to the server address closest to the user's geography , So as to speed up the parsing speed , Bring users a better access experience .