Hi ,
I am getting above warning in database event & message log file "alert_bgw.log" at the path given to "background_dump_dest" .

However db_create_file_dest and db_recovery_file_dest is indeed not the same. Looking in the alert_bgw.log during a startup, this is displayed:
db_create_file_dest = /var/opt/mediation/ora//oradata
db_recovery_file_dest = /var/opt/mediation/ora//flash_recovery_area

I am using Oracle on Solaris.
any idea why this warning is coming into log file will be highly appreciated.

Thanks in advance