Active/Active configuration is a redundancy method in which multiple system elements (devices, communication lines, etc.) with the same functionality are provided and combined to form an overall system. It is often used for web servers, application servers, etc., and its main purpose is to improve performance by load balancing. However, LB clusters also have the effect of increasing availability.
Active/Active configuration is one way to configure an HA cluster. For example, Active/Active configuration of two system elements usually improves performance because both are running. If one of the systems goes down, the remaining system takes over processing while the other takes over the state。
In contrast, there is another way to configure an HA cluster called Active/Standby configuration. In this configuration, usually only some system elements are active, while others are in standby. When a system element in the active state goes down, the system element in the standby state switches to the active state, and the system element in the standby state and the system element in the standby state are brought back up and running at the same time. If one of these system elements goes down, the other system elements take over the process.
Redundant configurations can be largely divided into "HA (High Availability) clusters" and "LB (Load Balance) clusters. It is usually used for database servers, etc., where data integrity is required, and its main purpose is, as the name suggests, to achieve high availability. On the other hand, LB clusters take over the "state" of the system elements when they take over the processing.。