How to create Datafiles in a Data Guard (10g) environment

OCP Rama Balaji explains how to create datafiiles in a Data Guard (10g) environment. She came across this Data Guard situation lately where a datafile was added to the primary database, but failed during creation on the standby.

I came across this Data Guard situation lately where a datafile was added to the primary database, but failed during creation on the standby. The database version was 10.2.0.3 and standby_file_management was set to AUTO.

Standby_file_management is a parameter, and when set to AUTO on the standby site, will create datafiles automatically on the standby site, for every datafile created on the primary site.

I started getting alerts in a few minutes on the standby for the following error.

 WARNING: File being created with same name as in Primary Existing file may be overwritten
File #309 added to control file as 'UNNAMED00309'.
Originally created as: '/disk1/oradata/primarydb01/sys06.dbf'
Recovery was unable to create the file as: '/disk1/oradata/primary/sys06.dbf'
Errors with log /disk1/archive/stbydb/sf2_1_215423_528599320.arc
MRP0: Background Media Recovery terminated with error 1119
Tue Feb 5 07:42:09 2008
Errors in file /disk1/oracle/admin/stbydb2/bdump/stbydb2_mrp0_12552.trc:
ORA-01119: error in creating database file '/disk1/oradata/sf12/sys06.dbf'
ORA-27054: NFS file system where the file is created or resides is not mounted with correct options
SVR4 Error: 13: Permission denied
Some recovered datafiles maybe left media fuzzy
Media recovery may continue but open resetlogs may fail
Tue Feb 5 07:42:13 2008
Errors in file /disk1/oracle/admin/stbydb2/bdump/stbydb2_mrp0_12552.trc:
ORA-01119: error in creating database file '/ora-disk/oradata/sf12/sys06.dbf'
ORA-27054: NFS file system where the file is created or resides is not mounted with correct options
SVR4 Error: 13: Permission denied
Tue Feb 5 07:42:13 2008

From the message it was clear that the datafile creation had failed on the standby, even though standby_file_management was set to AUTO. It failed for the reason that the directory the datafile was created in, "/disk1/oradata/primary/", was not there on the Physical Standby. However, we want the directory "/disk1/oradata/primary/" to be "/disk1/oradata/standby/" on the standby. This is taken care of by "DB_FILE_NAME_CONVERT" parameter set on the standby. However, if you have several lines for this parameter,

SQL> Show parameter db_file_name_convert

will display as empty. At that point, the only way to check that value is to view the parameter file.

So login to standby database and issue

Step 1: SQL> create pfile from spfile;

Now go to $ORACLE_HOME/dbs directory for that initialization parameter file.

In our case, we had clearly missed the directory that the datafile was created on the standby.

Change the pfile to add that destination

Db_file_name_convert= '/disk1/oradata/primary','/disk1/oradata/standby'

Step 2: Now login to the standby and cancel the recovery

SQL> alter database recover standby managed database cancel;

Database altered

Step 3: Shutdown and startup the standby database using new parameter file.

 

SQL> shutdown immediate;
ORA-01507: database not mounted

 

ORACLE instance shut down.

SQL> startup mount pfile=$ORACLE_HOME/dbs/initstandby.ora
ORACLE instance started.

 

 

 

SQL> create spfile from pfile;

Step 4: Start the managed recovery on the standby.

SQL> alter database recover managed standby database disconnect from session;

Database altered.

The above command will tell standby to start applying archivelogs from where it was missing. I got the following errors in the alert log this time:

 MRP0: Background Managed Standby Recovery process started (stbydb2)
Managed Standby Recovery not using Real Time Apply
MRP0: Background Media Recovery terminated with error 1111
Wed Feb 6 13:50:05 2008
Errors in file /disk1/oracle/admin/stbydb2/bdump/stbydb2_mrp0_22855.trc:
ORA-01111: name for data file 309 is unknown - rename to correct file
ORA-01110: data file 309: '/disk1/oracle/product/10.2.0/dbs/UNNAMED00309'
ORA-01157: cannot identify/lock data file 309 - see DBWR trace file
ORA-01111: name for data file 309 is unknown - rename to correct file
ORA-01110: data file 309: '/disk1/oracle/product/10.2.0/dbs/UNNAMED00309'
Wed Feb 6 13:50:05 2008
Errors in file /disk1/oracle/admin/stbydb2/bdump/stbydb2_mrp0_22855.trc:
ORA-01111: name for data file 309 is unknown - rename to correct file
ORA-01110: data file 309: '/disk1/oracle/product/10.2.0/dbs/UNNAMED00309'
ORA-01157: cannot identify/lock data file 309 - see DBWR trace file
ORA-01111: name for data file 309 is unknown - rename to correct file
ORA-01110: data file 309: '/disk1/oracle/product/10.2.0/dbs/UNNAMED00309'
Wed Feb 6 13:50:05 2008
MRP0: Background Media Recovery process shutdown (stbydb2)
Wed Feb 6 13:50:05 2008
Completed: alter database recover managed standby database disconnect from session
Wed Feb 6 13:52:09 2008
Using STANDBY_ARCHIVE_DEST parameter default value as /disk2/archive/stbydb2/
Redo Shipping Client Connected as PUBLIC
-- Connected User is Valid
RFS[1]: Assigned to RFS process 23024

This is because whenever datafile creation fails, Oracle server will create an invisible datafile called UNNAMED and make it look like it is there under $ORACLE_HOME/dbs. When the automatic recovery is resumed, it looks at that UNNAMED file, and the standby fails again with the message:

ORA-01111: name for data file 309 is unknown - rename to correct file

Now you need to rename that file to the one that you want to create in order for the physical standby to continue applying remaining logs.

Step 5: So now when you try to issue the "rename" command, you will get this error:

 SQL> alter database rename file '/disk1/oracle/product/10.2.0/dbs/UNNAMED00309' to
'/disk1/oradata/stbydb2/sys06.dbf'
*
ERROR at line 1:
ORA-01511: error in renaming log/data files
ORA-01275: Operation RENAME is not allowed if standby file management is automatic.

This is because RENAME (ADD/DROP,CREATE) operations on the standby is not allowed, when standby_file_manageent is set to AUTO. Now you need to change the parameter to MANUAL for the above command to work.

Step 6: SQL> alter system set STANDBY_FILE_MANAGEMENT=MANUAL scope=memory;

System altered.

 Step 7: SQL> alter database rename file
'/disk1/oracle/product/10.2.0/dbs/UNNAMED00309' to '/disk1/oradata/stbydb2/sys06.dbf';
alter database rename file '/disk1/oracle/product/10.2.0/dbs/UNNAMED00309' to '/disk1/oradata/stbydb2/sys06.dbf'
*
ERROR at line 1:
ORA-01511: error in renaming log/data files
ORA-01141: error renaming data file 309 - new file
'/disk1/oradata/stbydb2/sys06.dbf' not found
ORA-01111: name for data file 309 is unknown - rename to correct file
ORA-01110: data file 309:
'/disk1/oracle/product/10.2.0/dbs/UNNAMED00309'
ORA-27037: unable to obtain file status
SVR4 Error: 2: No such file or directory
Additional information: 3

 

Oh... What now? Well, we can not rename to a file that doesn't already exist, so we actually need to create the datafile.

Step 8: SQL> alter database create datafile
'/disk1/oracle/product/10.2.0/dbs/UNNAMED00309' as '/disk1/oradata/stbydb2/sys06.dbf';

Database altered.

Yes, finally! Ok, datafile created. Let's put the automatic recovery back on the standby.

Step 9: SQL> alter database recover standby database;
alter database recover standby database
*
ERROR at line 1:
ORA-00279: change 9999250009 generated at 02/05/2008 07:28:43 needed for thread 1
ORA-00289: suggestion : /disk2/archive/stbydb2/sf2_1_215423_528599320.arc
ORA-00280: change 9999250009 for thread 1 is in sequence #215423

 

Now Oracle wants me to manually specify the archive log files to be applied. This is because I changed the standby_file_management parameter earlier to MANUAL. I need to put it back to AUTO.

Step 10: SQL> alter system set STANDBY_FILE_MANAGEMENT=AUTO scope=memory;

System altered.

Step 11: Now issue the command
SQL> recover automatic standby database;

Media recovery complete.

Check the alert log

Tail –f alert*

 RFS[1]: Assigned to RFS process 27167
RFS[1]: Identified database type as 'physical standby'
Wed Feb 6 14:48:32 2008
RFS LogMiner: Client disabled from further notification
Wed Feb 6 14:48:45 2008
Media Recovery Log /disk2/archive/stbydb2/sf2_1_215425_528599320.arc
Wed Feb 6 14:50:04 2008
RFS[1]: No standby redo logfiles created
Wed Feb 6 14:51:32 2008
RFS[1]: Archived Log: '/disk2/archive/stbydb2/sf2_1_215542_528599320.arc'
Wed Feb 6 14:56:42 2008
Recovery created file /disk1/oradata/stbydb2/users121.dbf
Successfully added datafile 310 to media recovery
Datafile #310: '/disk1/oradata/stbydb2/users121.dbf'

 

Yes, it successfully created the datafile and the recovery resumed. All the missing 105 archive log files were applied against 2.5TB OLTP database.

Best practices and lesson learned: Whenever you add a datafile to the primary, login to standby and make sure it was created successfully. The best way to do that is to issue "tail –f alert*" in the background_dump_dest directory. If for some reason the datafile creation has failed, cancel the recovery on the standby, and do only the steps 6, 8, 10 and 11 in this document.

About the Author: Rama Balaji is a Oracle Certified Professional with 16+ years of Oracle experience in maintaining and trouble shooting very critical production databases. She has been working as an Oracle consultant for various clients in finance, telecommunications, and the government agencies, specializing in database tuning with extensive experience in RMAN, Data Guard, RAC and ASM. Rama Balaji is currently employed with TUSC (The Ultimate Software Consultants)-A Rolta Company.

Total System Global Area 2147483648 bytes
Fixed Size > 2074152 bytes
Variable Size 1056967128 bytes
Database Buffers 1073741824 bytes
Redo Buffers 14700544 bytes
Database mounted.
This was first published in February 2008

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