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Mouhamadou Diaw

Online datafile move in a 12c dataguard environment

Oracle 12c introduces moving online datafile. One question we might ask is what about moving datafile online in a dataguard environment. In this blog we will do some tests
Below our configuration, we are using oracle 12.2

DGMGRL> show configuration;
Configuration - MYCONT_DR
Protection Mode: MaxPerformance
Members:
MYCONT_SITE - Primary database
MYCONT_SITE1 - Physical standby database
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS (status updated 8 seconds ago)
DGMGRL>

The StandbyFileManagement property is set to auto for both primary and standby database.

DGMGRL> show database 'MYCONT_SITE' StandbyFileManagement;
StandbyFileManagement = 'auto'
DGMGRL> show database 'MYCONT_SITE1' StandbyFileManagement;
StandbyFileManagement = 'auto'
DGMGRL>

Below datafiles on both primary and standby pluggable databases PDB1

SQL> show con_name;
CON_NAME
------------------------------
PDB1
SQL> select name from v$datafile;
NAME
-------------------------------------------------------
/u01/app/oracle/oradata/MYCONT/PDB1/system01.dbf
/u01/app/oracle/oradata/MYCONT/PDB1/sysaux01.dbf
/u01/app/oracle/oradata/MYCONT/PDB1/undotbs01.dbf
/u01/app/oracle/oradata/MYCONT/PDB1/users01.dbf

Now let’s move for example /u01/app/oracle/oradata/MYCONT/PDB1/users01.dbf to a new location on the primary PDB1

SQL> alter database move datafile '/u01/app/oracle/oradata/MYCONT/PDB1/users01.dbf' to '/u01/app/oracle/oradata/MYCONT/PDB1/newloc/users01.dbf';
Database altered.
SQL>

We can verify the new location on the primary

SQL> select name from v$datafile;
NAME
-------------------------------------------------------
/u01/app/oracle/oradata/MYCONT/PDB1/system01.dbf
/u01/app/oracle/oradata/MYCONT/PDB1/sysaux01.dbf
/u01/app/oracle/oradata/MYCONT/PDB1/undotbs01.dbf
/u01/app/oracle/oradata/MYCONT/PDB1/newloc/users01.dbf
SQL>

As the StandbyFileManagement is set to auto for both databases, we might think that datafile is also moved in the standby, so let’s check

SQL> select name from v$datafile;
NAME
-------------------------------------------------------
/u01/app/oracle/oradata/MYCONT/PDB1/system01.dbf
/u01/app/oracle/oradata/MYCONT/PDB1/sysaux01.dbf
/u01/app/oracle/oradata/MYCONT/PDB1/undotbs01.dbf
/u01/app/oracle/oradata/MYCONT/PDB1/users01.dbf

The answer is no.
Ok but is my dataguard still working? Let’s query the broker

DGMGRL> show configuration;
Configuration - MYCONT_DR
Protection Mode: MaxPerformance
Members:
MYCONT_SITE - Primary database
MYCONT_SITE1 - Physical standby database
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS (status updated 0 seconds ago)

Yes the configuration is fine.
Ok now can I move online my datafile in the new location on the standby server? Let’s try

SQL> alter database move datafile '/u01/app/oracle/oradata/MYCONT/PDB1/users01.dbf' to '/u01/app/oracle/oradata/MYCONT/PDB1/newloc/users01.dbf';
Database altered.
SQL>

And we can verify that datafile was moved.

SQL> select name from v$datafile;
NAME
-------------------------------------------------------
/u01/app/oracle/oradata/MYCONT/PDB1/system01.dbf
/u01/app/oracle/oradata/MYCONT/PDB1/sysaux01.dbf
/u01/app/oracle/oradata/MYCONT/PDB1/undotbs01.dbf
/u01/app/oracle/oradata/MYCONT/PDB1/newloc/users01.dbf
SQL>

And we also can verify that my dataguard configuration is still fine

DGMGRL> show configuration;
Configuration - MYCONT_DR
Protection Mode: MaxPerformance
Members:
MYCONT_SITE - Primary database
MYCONT_SITE1 - Physical standby database
Fast-Start Failover: DISABLED
Configuration Status:
SUCCESS (status updated 46 seconds ago)
DGMGRL>

Conclusion
We can see that
1- StandbyFileManagement property dos not concern online datafile move
2- Moving online datafile in the primary does not move the datafile on the standby
3- Online datafile can be done on the standby database

 

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Mouhamadou Diaw
Mouhamadou Diaw

Consultant