LEMP (also known as LNMP) is a group of open-source software which enable a server to host dynamic websites and web applications. It consists of the Linux operating system, the (E)Nginx web server (which replaces the Apache component of a LAMP stack), the MySQL relational database management system, and the PHP programming language.
MySQL replication is a process that enables data from one MySQL database server (the master) to be copied automatically to one or more MySQL database servers (the slaves). Replication is asynchronous by default. Slaves do not need to be connected permanently to receive updates from the master. Depending on the configuration, you can replicate all databases, selected databases, or even selected tables within a database.