Losing Datafiles Whenever you are in NoArchivelog Mode:
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If you are in noarchivelog mode and you loss any datafile then whether it is temporary or permanent media failure, the database will automatically shut down. If failure is temporary then correct the underline hardware and start the database. Usually crash recovery will perform recovery of the committed transaction of the database from online redo log files. If you have permanent media failure then restore a whole database from a good backup. How to restore a database is as follows:
If a media failure damages datafiles in a NOARCHIVELOG database, then the only option for recovery is usually to restore a consistent whole database backup. As you are in noarchivelog mode so you have to understand that changes after taken backup is lost.
If you logical backup that is export file you can import that also.
In order to recover database in noarchivelog mode you have to follow the following procedure.
1)If the database is open shutdown it.
SQL>SHUTDOWN IMMEDIATE;
2)If possible, correct the media problem so that the backup database files can be restored to their original locations.
3)Copy all of the backup control files, datafiles to the default location if you corrected media failure. However you can restore to another location. Remember that all of the files not only the damaged files.
4)Because online redo logs are not backed up, you cannot restore them with the datafiles and control files. In order to allow the database to reset the online redo logs, you must have to do incomplete recovery:
RECOVER DATABASE UNTIL CANCEL
CANCEL
5)Open the database in RESETLOGS mode:
ALTER DATABASE OPEN RESETLOGS;
In order to rename your control files or in case of media damage you can copy it to another location and then by setting (if spfile)
STARTUP NOMOUNT
alter system set control_files='+ORQ/orq1/controlfile/control01.ctl','+ORQ/orq1/controlfile/control02.ctl' scope=spfile;
STARTUP FORCE MOUNT;
In order to rename data files or online redo log files first copy it to new location and then point control file to new location by,
ALTER DATABASE RENAME FILE '+ORQ/orq1/datafile/system01.dbf';'
TO '+ORQ/orq1/datafile/system02.dbf';
Losing Datafiles Whenever you are in Archivelog Mode:###################################################
If the datafile that is lost is under SYSTEM tablespace or if it is a datafile contain active undo segments then database shuts down. If the failure is temporary then correct the underline hardware and start the database. Usually crash recovery will perform recovery of the committed transaction of the database from online redo log files.
If the datafile that is lost in not under SYSTEM tablespace and not contain active undo segments then the affected datafile is gone to offline. The database remains open. In order to fix the problem take the affected tablespace offline and then recover the tablespace.
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If you are in noarchivelog mode and you loss any datafile then whether it is temporary or permanent media failure, the database will automatically shut down. If failure is temporary then correct the underline hardware and start the database. Usually crash recovery will perform recovery of the committed transaction of the database from online redo log files. If you have permanent media failure then restore a whole database from a good backup. How to restore a database is as follows:
If a media failure damages datafiles in a NOARCHIVELOG database, then the only option for recovery is usually to restore a consistent whole database backup. As you are in noarchivelog mode so you have to understand that changes after taken backup is lost.
If you logical backup that is export file you can import that also.
In order to recover database in noarchivelog mode you have to follow the following procedure.
1)If the database is open shutdown it.
SQL>SHUTDOWN IMMEDIATE;
2)If possible, correct the media problem so that the backup database files can be restored to their original locations.
3)Copy all of the backup control files, datafiles to the default location if you corrected media failure. However you can restore to another location. Remember that all of the files not only the damaged files.
4)Because online redo logs are not backed up, you cannot restore them with the datafiles and control files. In order to allow the database to reset the online redo logs, you must have to do incomplete recovery:
RECOVER DATABASE UNTIL CANCEL
CANCEL
5)Open the database in RESETLOGS mode:
ALTER DATABASE OPEN RESETLOGS;
In order to rename your control files or in case of media damage you can copy it to another location and then by setting (if spfile)
STARTUP NOMOUNT
alter system set control_files='+ORQ/orq1/controlfile/control01.ctl','+ORQ/orq1/controlfile/control02.ctl' scope=spfile;
STARTUP FORCE MOUNT;
In order to rename data files or online redo log files first copy it to new location and then point control file to new location by,
ALTER DATABASE RENAME FILE '+ORQ/orq1/datafile/system01.dbf';'
TO '+ORQ/orq1/datafile/system02.dbf';
Losing Datafiles Whenever you are in Archivelog Mode:###################################################
If the datafile that is lost is under SYSTEM tablespace or if it is a datafile contain active undo segments then database shuts down. If the failure is temporary then correct the underline hardware and start the database. Usually crash recovery will perform recovery of the committed transaction of the database from online redo log files.
If the datafile that is lost in not under SYSTEM tablespace and not contain active undo segments then the affected datafile is gone to offline. The database remains open. In order to fix the problem take the affected tablespace offline and then recover the tablespace.
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