Limited distance between 2 nodes in a cluster using Oracle RAC 11gR2
My company are buying a multimedia content management system. We want to deploying it on 2 sites (their distance = 1500km) and want to sync database between them. Each site is a complete system that can work without other site. The system requirement for database on this system is Oracle RAC 11gR2. I find some info on google which said that 2 nodes in a cluster must be < 100 km but i can't verify this.
If this info is true, is there other solution else to synchronize database between 2 or more very far sites ?
Oh, the most important thing i want to know is limited distace between 2 nodes.