To understand distributed systems, you mainly need to understand two aspects:
1. A distributed system must be a system composed of multiple nodes.
Among them, nodes refer to computer servers, and these nodes are generally not isolated, but interconnected.
2. Our nodes are deployed on these connected nodes, and mutual operations will be coordinated.
For users in a distributed system, what they face is a server that only provides the services that users need. In fact, these services are a distributed system composed of many servers behind them. So the distributed system looks like a supercomputer.
Taobao, for example, is used by everyone and is itself a distributed system. When we access the Taobao website through a browser, behind this request is a huge distributed system providing services for us. Some of the entire system are responsible for request processing, some are responsible for storage, and some are responsible for calculation. In the end, they coordinate with each other. The final results are returned and presented to the user.
The main features of using distributed systems are as follows:
1. Increase system capacity
Our business volume is getting larger and larger, and we need to To cope with the increasing business volume, the performance of one machine can no longer meet the requirements. We need multiple machines to cope with large-scale application scenarios. Therefore, we need to split the business system vertically or horizontally and turn it into a distributed architecture.
2. Enhance system availability
Our business is becoming more and more critical, and we need to improve the availability of the entire system architecture, which means that there cannot be a single point of failure in the architecture. In this way, the entire system will not become unavailable due to the failure of one machine. Therefore, it is necessary to redundant the system through a distributed architecture to eliminate single points of failure and thereby improve system availability.
3. Because of modularization, system modules are more reusable
4. Because software service modules are split, development and release can be done in parallel and become faster
5. The system is more scalable
6. The team collaboration process will also be improved
There are three types of distributed systems:
1. Distributed processing, but there is only one total database and no local database.
2. Hierarchical processing, each layer has its own database.
3. A fully decentralized distributed network without a central control part. There can be many ways of contact between nodes, such as loose connection, tight connection, dynamic connection, and broadcast notification type. Connections etc.
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