An Ingres instance consists of a set of installed products that share a unique system-file location, ownership, and instance name, together with any data files created by these products. An instance is classified as either a server installation or a client installation.

A server installation consists of a DBMS server process (iidbms), a Name Server process (iigcn), a set of tools, and the files and logs necessary to run the DBMS Server.

If the server installation allows remote clients to access its DBMS servers, the server installation also includes the Ingres Net Communications Server process (iigcc).

A client installation contains a Name server process (iigcn), a Communications server process (iigcc), a Data Access Server process (iigcd), the API components that support client applications (JDBC Driver, ODBC Driver and .NET Data Provider) and the tools. A client installation does not run a DBMS server or store any data.