When DB is running again then just make a touch to datasource file. This will redeploy all mbean related with datasource and restart conection pool.
After this touch your system will work fine again.
Thanks. The problem is access to production environment. I'm thinking of automating these steps. May be i have to write a connection-checker class and add the entry to -ds.xml file. This connection-checker class will check for connection and redeploy the mbean. Other approach would be to handle it programatically in the code where you get a connection from Datasource, we can redeploy the datasource again using the Mbean.