If you are the kind of datacenter customer whose database and application server deployments are limited by the license fees based on core count, then you have the perfect solution from Sun that frees your data centre from core count and your mind from license worries by going for the unlimited Glassfish + MySQL deployment for a flat fee based on the number of employees.
For a comparison of the TCO, check the details here.
Of course for additional HA capabilities including DR, you can use Solaris Cluster with its robust monitoring, low costs and excellent stability.