ZEO - Single-server client-server database server for ZODB

ZEO is a client-server storage for ZODB http://www.zodb.org 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.