Clustering, Distributed, Load Balancing Differences and Connections

1. Linux clusters are mainly divided into three categories (high availability clusters, load balancing clusters, scientific computing clusters) (only load balancing clusters are introduced below)
Load Balance Cluster
Load balancing system: all nodes in the cluster are active states, they share the workload of the system. General Web server clusters, database clusters and application server clusters belong to this type.

Load balancing clusters are generally used for web servers and database servers corresponding to network requests. This kind of cluster can check the less busy and less busy servers when receiving requests, and forward the requests to these servers. From the point of view of checking the status of other servers, load balancing and fault tolerant clusters are very close, the difference is that they are more numerous.


2. Load balancing system: Load balancing has DNS load balancing (more commonly used), IP load balancing, reverse proxy load balancing, etc., that is, there are servers A, B, and C in the cluster, which do not affect each other. Irrelevant, if any machine goes down, it will not affect the operation of other machines. When a user makes a request, the algorithm of the load balancer determines which machine will process it. If your algorithm uses the round algorithm, If there are users a, b, and c, they are handled by servers A, B, and C respectively;


3. Distributed means that different services are distributed in different places.
Clustering refers to grouping several servers together to achieve the same business.
Each node in the distribution can be used as a cluster.
Clusters are not necessarily distributed.
For example: Take Sina.com, for example, if there are many people accessing it, he can make a cluster, put a response server in front, and several servers in the back to complete the same business. If there is business access, the response server can see which server is not very loaded. If it is heavy, which one will be used to complete it.
Distributed, in a narrow sense, is similar to a cluster, but its organization is relatively loose, unlike a cluster, which has an organization. If one server fails, other servers can come up.
Each distributed node completes a different business. If a node fails, the business cannot be accessed.