Hi Suhas
Unfortunately we do not support mirrored database so be careful with your setup and test it very thoroughly. I am aware of issues when running DWH job and others.
If you want to change the setting of PPM/DWH database - these in Jaspersoft are taken from the properties.xml file and database connections there. So for those to be updated you have to run the command:
admin update jasperParameters
This command will update the profile parameters in the Jaspersoft server. After that you could change the properties.xml and not run the command to keep the connections to previous data.
Hope this helps -Nika