How to use active database duplication for creating a physical standby

When you use active database duplication for creating a physical standby database, make sure of the following:

1. keep your pfile used to start an auxiliary instance to a minimum. Only the following lines are needed:

db_block_size=8192
db_name='proddb01'

Of course, the db_name must be identical to the db_name of the primary database.

2. In your duplication script, make sure you the spfile contains a correct value for db_unique name:

run{
        allocate channel c1 type disk;
        allocate channel c2 type disk;
        allocate channel c3 type disk;
        allocate channel c4 type disk;
        allocate auxiliary channel stby type disk;
duplicate target database for standby from active database
spfile
SET db_unique_name='stby01'
SET db_domain='mydomain.no'
SET FAL_CLIENT='stby01'
SET FAL_SERVER='proddb01'
SET log_archive_dest_1='location=use_db_recovery_file_dest valid_for=(ALL_LOGFILES,ALL_ROLES) DB_UNIQUE_NAME=stby01'
SET log_archive_dest_2=''
SET control_files='/data1/oradata/stby01/control01.ctl','/data2/fra/stby01/control02.ctl'
SET STANDBY_FILE_MANAGEMENT='MANUAL'
SET LOG_ARCHIVE_MAX_PROCESSES='2'
SET local_listener='stby01.skead.no'
SET dg_broker_config_file1='/sw/oracle/product/12201/dbs/dr1stby01.dat'
SET dg_broker_config_file2='/sw/oracle/product/12201/dbs/dr2stby01.dat'
SET LOG_ARCHIVE_CONFIG='DG_CONFIG=(stby01,proddb01)'
SET diagnostic_dest='/sw/oracle'
SET db_recovery_file_dest='/data2/fra'
SET db_file_name_convert='/data1/oradata/proddb01','/data1/oradata/stby01'
SET log_file_name_convert='/data3/oradata/proddb01','/data3/oradata/stby01'
NOFILENAMECHECK;
}

Note that the directive "spfile" used right before the individual SET commands does not mean "create spfile". It means "fetch spfile from primary". The SET commands, however, will be written to your local spfile which will then be used to start the auxiliary instance once more, before the actual cloning starts.

When the duplicaton has finished, the value of "db_name" parameter will be identical to the primary database, since we are fetching the spfile from your primary database server over the network.

How to solve "RMAN-04014: startup failed: ORA-01261: Parameter db_recovery_file_dest destination string cannot be translated" during cloning

During an attempt to clone for active database I had created pfile with my desired value for the parameter db_recovery_file_dest, which was /fradata. Excerpt from init.ora used to start the instance (nomount):

cat initproddb01.ora |grep db_recovery_file_dest

*.db_recovery_file_dest='/fradata'

This directory exists on my auxilliary server and is indeed writable by the oracle software installation owner (for most installation, this user is called "oracle") After having started the instance, and executed the clone script:

DUPLICATE TARGET DATABASE
FOR STANDBY
FROM ACTIVE DATABASE
DORECOVER
SPFILE
SET DB_UNIQUE_NAME='STBY01' COMMENT 'Stanby db 1'
USING COMPRESSED BACKUPSET
NOFILENAMECHECK;

This message appears:

RMAN-00571: ===========================================================
RMAN-00569: =============== ERROR MESSAGE STACK FOLLOWS ===============
RMAN-00571: ===========================================================
RMAN-03002: failure of Duplicate Db command at 04/13/2021 08:07:31
RMAN-05501: aborting duplication of target database
RMAN-03015: error occurred in stored script Memory Script
RMAN-04014: startup failed: ORA-01261: Parameter db_recovery_file_dest destination string cannot be translated
ORA-01262: Stat failed on a file destination directory
Linux-x86_64 Error: 2: No such file or directory

Cause: The spfile that is created contains the target's db_recovery_file_dest setting, not the auxiliary's:

strings spfileproddb01.ora | grep db_recovery_file_dest
*.db_recovery_file_dest='/FRA' <--- this is inherited from the target database, and doesn't exist on the auxiliary server

Solution: Add a new spfile directive to your clone script:

SET DB_RECOVERY_FILE_DEST='/fradata'

and rerun.