ZEO is a client-server storage for ZODB for sharing a single storage among many clients. When you use ZEO, a lower-level storage, typically a file storage, is opened in the ZEO server process. Client programs connect to this process using a ZEO ClientStorage. ZEO provides a consistent view of the database to all clients. The ZEO client and server communicate using a custom protocol layered on top of TCP. There are several features that affect the behavior of ZEO. This section describes how a few of these features work. Subsequent sections describe how to configure every option.