Thursday, November 11, 2010

Oracle Database Recovery from its Backups

Recovery and backup are the most important aspects of database job. If anyone lose their company's data, he/she could very well lose his/her job. Software and hardware can always be replaced but data may not be replaceable. For smooth functioning of any organization/company good recovery and backup technique is required. You can schedule your backup policy on daily, weekly or monthly basis. Consider a situation, you are working on the company project and your database gets corrupted and backup is not managed, at that situation you should use an advanced database recovery software to recover database.

Backup frequency of any database normally depend upon the given below factors

    Criticality of the data/ Value of the data to the organization. Rate of data change/ transaction rate. Read-only tablespace needs backup just once right after you make it read-only. If you are running in archivelog mode you can backup parts of a database over an extended cycle of periods. Etc.

Oracle Database Backing-up strategies: Various strategies are available for backing-up of Oracle database.

Export/Import: Export is the logical database backup in which they extract logical definitions and data from the database to a file.

Off-line Backup: It is also known as cold backup. Shutdown the database and backup all the logs, control files and data.

On-line Backup: It is also known as hot backup. If the database is in ARCHIVELOG mode, set the tablespaces into backup mode and backup their files.

RMAN Backup: RMAN utility is used to backup database while database is in off-line or online mode.

Difference between online and offline backup
: There are so many difference between online and offline backup. Some of them is given below:

    Online backup is performed when database is open and available for the user while offline backup is performed wher database is unavailable for its users. It is easier to restore from the offline backup than online backup. Point-in-time recovery method is available in the online backup while it is unavailable in the offline backup.

Your Oracle database got damaged and none of above backups are available, you could use stellar oracle database recovery software to recover your database. This software is read only in nature. This Oracle recovery software completely repairs and restores all Oracle database objects, such as tables, table spaces, schemas, views, roles, constrains, indexes and sequences.

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