将APEX安装在Oracle RAC上

APEX could be installed on Oracle RAC. Some of the advantages are as follows:
1. To ensure maximum uptime. For a 2 nodes RAC env, individual nodes can be shutdown for maintenance while APEX application
uses continue to work. 
2. To provide greater throughput and scalability than normally available from a string server.

Here is a paper from OTN to provide with an overview of steps on configuring an Oracle APEX instace for a Oracle Real Application Clusters(RAC) database:

http://www.oracle.com/technetwork/developer-tools/apex/learnmore/apex-rac-wp-133532.pdf