What is "clustering" in EJB?

Clustering refers to the ability of multiple load-balanced web servers to share session and entity data. It is a major feature of web application servers. Standardized support for clustering was one of the primary motivations behind the EJB spec.

Clustering also applies to Servlet containers sharing HttpSession data (similar to EJB Session Beans).

For more information, see the following questions on the Servlet FAQ:

• What servlet engines support clustering -- that is, sharing of session data across multiple load-balanced web servers?