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.Restart the database.After you have finished backing up all datafiles and a single control fileof the database, you can restart the database.Verifying BackupsDB_VERIFY is a command-line utility that performs a physical data structureintegrity check on database files.Use DB_VERIFY primarily when you need toensure that a backup database (or datafile) is valid before it is restored.See Also: For more information about making operating system backups offiles, see your operating system-specific Oracle documentation.For more information on DB_VERIFY, see the Oracle7 Server Utilities guide.Performing Tablespace, Datafile, Control File or Archivelog BackupsTablespace, datafile, control file and archivelog backups should only be taken(and in some cases can only be taken) if a database is operating inARCHIVELOG mode.Such backups cannot be used to restore a databaseoperating in NOARCHIVELOG mode.Backing Up Online Tablespaces and DatafilesYou can back up all datafiles of an individual online tablespace or specificdatafiles of an online tablespace while the database is open.When you back up an individual datafile or online tablespace, Oracle stopsrecording the occurrence of checkpoints in the headers of the online datafilesbeing backed up.Oracle stops recording checkpoints as a direct result ofissuing the ALTER TABLESPACE BEGIN BACKUP statement.This means thedatabase is in hot backup mode, and that when a datafile is restored, it has knowledge of the most recent datafile checkpoint that occurred before theonline tablespace backup, not any that occurred during it.As a result, Oracleasks for the appropriate set of redo log files to apply should recovery be10-4 Oracle8 Backup and Recovery Guide needed.After the datafile copy is completed, Oracle advances the file headerto the current database checkpoint.This is done after the ALTERTABLESPACE END BACKUP statement is executed.To Back Up Online Tablespaces in an Open Database:Identify the datafiles.If you are backing up a specific datafile, use the fully specified filenameof the datafile.Before beginning a backup on an entire tablespace, identify all of thetablespace s datafiles using the DBA_DATA_FILES data dictionaryview.For example, assume that the USERS tablespace is to be backedup.To identify the USERS tablespace s datafile, you can query theDBA_DATA_FILES view:SELECT tablespace_name, file_nameFROM sys.dba_data_filesWHERE tablespace_name = USERS ;TABLESPACE_NAME FILE_NAME--------------- ---------USERS filename1USERS filename2Here, filename1 and filename2 are fully specified filenamescorresponding to the datafiles of the USERS tablespace.4.Mark the beginning of the online tablespace backup.To prepare the datafiles of an online tablespace for backup (and putthem in hot backup mode), use either the Start Online Backup menuitem of Enterprise Manager, or the SQL command ALTERTABLESPACE with the BEGIN BACKUP option.The following statement marks the start of an online backup for thetablespace USERS:ALTER TABLESPACE users BEGIN BACKUP;Warning: If you forget to mark the beginning of an online tablespace backup,or neglect to assure that the BEGIN BACKUP command has completed beforebacking up an online tablespace, the backup datafiles are not useful forsubsequent recovery operations.Attempting to recover such a backup is arisky procedure, and can return errors that result in inconsistent data later.ForPerforming Operating System Backups 10-5 example, the attempted recovery operation will issue a fuzzy files warning,and lead to an inconsistent database that will not open.5.Back up the online datafiles.At this point, you can back up the online datafiles of the onlinetablespace from within Enterprise Manager, using the HOST command,by exiting Enterprise Manager and entering the operating systemcommands, or starting the Backup utility6.Mark the end of the online tablespace backup
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