There are some reasons for a file being created as UNNAMED in the standby database, including insufficient disk space on the standby site, non-privileged directory structure on standby database, or improper parameter settings related to file management.

The STANDBY_FILE_MANAGEMENT parameter enables or disables automatic standby file management in Data Guard. When automatic standby file management is enabled, file additions and deletions in the primary database are replicated to the standby database.

For example, we add a datafile in the primary database when the STANDBY_FILE_MANAGEMENT parameter on the standby database is set to MANUAL. Due to this parameter setting, it will create an UNNAMED file under $ORACLE_HOME/dbs, and this will cause the MRP process to be killed. Errors in the alert log file will be as follows:

Errors in file /u01/app/oracle2/diag/rdbms/india_ps/INDIAPS/trace/INDIAPS_pr00_691.trc:
ORA-01111: name for data file 10 is unknown - rename to correct file
ORA-01110: data file 10: ' /u01/app/oracle2/product/11.2.0/dbhome_1/dbs/UNNAMED00010'
ORA-01157: cannot identify/lock data file 10 - see DBWR trace file