For HP ALM Performance Center Edition, You will need a separate physical server machine for the ALM Server.

PC Server will access the DB through ALM . Attached is the HP ALM-PC Database Best Practice Guide as a reference.

The ALM platform handles the database setup and communications. The Performance Center will access files and data through ALM as needed. Performance Center does not have its own Schema/Tables outside of those associated with ALM. Please see pic attached ''ALM-PC_Arch.jpg''

''ALM uses two Database User Schemas:

Site Administration Database User Schema

This schema maintains all site administration tables (for example, USERS, PROJECTS, and so on). There is only one such schema for each ALM site. This schema is created at the time of installation.

Project Database User Schema

This schema maintains all data related to a specific project. The number of projects, as well as the size of the database user schemas, varies according to the implementation.

ALM is a multi-tier application. The clients communicate with the application server in a proprietary protocol. The application server communicates with the database by using Java Database Connectivity (JDBC).
The database JDBC driver is a type 4 driver. As a result, no database client is required to be installed on the application server.''