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Advantages Disadvantages for open Database Backup

Business transactions will not be interrupted during the backup

Maintain high database availability -
When using an open database backup, the database is available for process access during the backup and the business transactions will not be interrupted because of the backup.
More training required for the DBA -
Because an open database backup is a complicated process (compared to the closed database backup), a DBA will need more training to handle the process.
Can be done at a tablespace or datafile level -
A DBA may choose to backup all the datafiles for a specific tablespace or just individual datafiles for a tablespace.
More error-prone -
An online database backup is more error-prone because of additional operator interaction. Thus, it's best to use tested scripts to automate the process.
Allows recovery to point-in-time -
With an open database backup, the DBA may choose to recover the database to a certain point of time.

Overview of Database Backup and Recovery

The focus in Oracle Database backup and recovery is on the physical backup of database files, which permits you to reconstruct your database. Oracle Recovery Manager (RMAN), a command-line tool, is the method preferred by Oracle for efficiently backing up and recovering your Oracle database. The files protected by the backup and recovery facilities built into RMAN include
  1. data files,
  2. control files,
  3. server parameter files, and
  4. archived redo log files.
With these files you can reconstruct your database. RMAN is designed to work intimately with the server, providing block-level corruption detection during backup and restore. RMAN optimizes performance and space consumption during backup with file multiplexing and backup set compression, and integrates with leading tape and storage media products. The backup mechanisms work at the physical level to protect against file damage, such as the accidental deletion of a data file or the failure of a disk drive. RMAN can also be used to perform point-in-time recovery to recover from logical failures when other techniques such as flashback cannot be used. Logical backups, such as exporting database objects such as tables or tablespaces, are a useful supplement to physical backups, but cannot protect your whole database. An effective backup strategy must be based on physical backups. The Oracle Database flashback features provide a range of physical and logical data recovery tools as efficient, easy-to-use alternatives to physical and logical backups. The flashback features enable you to reverse the effects of unwanted database changes without restoring data files from backup.