Talking about the understanding of CAP in distributed mode

1. First of all, what does cap stand for

c stands for Consistency

a stands for availability

p stands for fault tolerance

2. A distributed system can satisfy at most two of the three characteristics of Consistency (consistency), Availability (availability), and Partition tolerance (partition tolerance). The three are not compatible.

3. Detailed description

Consistency means: under the requirement of consistency, when a system performs an update operation in a state of consistent data, it should ensure that the data of the system is still in a consistent state.

Availability means: the services provided by the system must always be available, and the results can always be returned within a limited time for each operation request of the user.

Partition fault tolerance means that when a distributed system encounters any network partition failure, it still needs to be able to provide services that meet the consistency and availability to the outside world, unless the entire network environment fails.

4. List such as:

Zk cluster ensures CP, redis cluster ensures AP