Each site in the Multisite network sharing the same WordPress installation means all the sites share the same database and must be installed on the same server.
Having a shared database between sites in a WordPress Multisite installation makes it easier to access and transfer data between each site. For example, user accounts can be registered to multiple sites. It also means if one site in the network is hacked it compromises other sites on the network.
A WordPress Multisite installation also shares code between all sites. This means that WordPress themes and plugins are installed to the entire site network rather than being installed at the individual site level. However, plugins and themes can be activated and deactivated on a per-site basis.
Read about WordPress Hosting, Wordpress for the Enterprise, and how to make the most of the WordPress Gutenberg editor.
WordPress Multisite vs. Multiple Single WordPress Installations
Multisite | Single Installations | |
---|---|---|
Database shared between sites | Yes | No |
Codebase shared between sites | Yes | No |
Server resources shared between sites | Yes | Yes or No* |
User accounts shared between sites | Yes | No |
Risk of all sites going down if there are issues | Yes | No |
Plugins and themes need must be updated per-site | No | Yes |