What are the advantages and disadvantages of local mirror database and remote database master station?

First of all, except that the database and the program are on the same machine, whether the database runs on the same router or on a server outside the data center hundreds of kilometers away, it is collectively called an external database.

The advantages of external database are obvious: the hardware is dedicated, the security of executing a single service is greatly improved, clustering can be easily realized, and data redundancy can be realized. Disadvantages are also obvious: hardware needs to be added, the data transmission speed depends on the connection speed between servers, and if it is a remote host, the transmission delay is also a big problem.

The advantage of local database is naturally that it saves hardware and is relatively convenient in basic management, and the data transmission between application and database is basically unrestricted. The disadvantage is that it is too dependent on the host. If the server goes down because of an application problem, the database will naturally be implicated. Unable to achieve cluster redundancy and so on.