19 物理备份.ppt

物理备份 Terminology Whole database backup Target database may be open or closed Backup of all datafiles and the control file Partial database backups Tablespace Data file Control file Consistent backups Inconsistent backups User-Managed Backup and Recovery Files are backed up with operating system commands Backups are restored with operating system commands Recovery is accomplished using SQL and SQL*Plus commands Querying Views to Obtain Database File Information Backup Methods Consistent Whole Database Backup(Closed Database Backup) Advantages of Making Consistent Whole Database Backups Conceptually simple Easy to perform Require little operator interaction Making a Consistent Whole Database Backup Open Database Backup Advantages of MakingOpen Database Backups Maintains high database availability Can be done at a tablespace or datafile level Supports nonstop business operations Open Database Backup Requirements Open Database Backup Options Making a Backup of an Online Tablespace Ending the Online Tablespace Backup Backup Status Information Failure During Online Tablespace Backup Ending the Online Backup Query V$BACKUP to check backup status Issue the ALTER DATABASE command to change the status and unfreeze the header: Or use this command in Oracle9i: Read-Only Tablespace Backup Read-Only Tablespace Backup Issues Only one backup is needed after altering the tablespace to read-only. Resume a normal backup schedule for that tablespace after making it read-write. The control file must correctly identify the tablespace in read-only mode; otherwise you must recover it. Backup Issues with LOGGING and NOLOGGING Options Manual Control File Backups Creating a binary image Creating a text trace file Backing Up the Initialization Parameter File Verifying Backups Using the DBVERIFY Utility DBVERIFY Command-Line Interface External command-line utility Used to ensure that a backup database or datafile is valid before a restore Can be a helpful diagnostic aid when data