Backup is used to prevent data loss in case of corruption or other disaster. Having an updated backup is the first step in disaster recovery planning of any database. Similarly Oracle provides various backup and recovery solutions that you can implement.
Recovery Manager (RMAN) is used for backup and recovery of Oracle database. It is considered as most preferred backup strategy due to its amazing features. One of the great features of RMAN is that it detects and repairs block corruption. RMAN can be accessed through command line or Oracle Enterprise Manager. Some of the key features of RMAN are:
- It generates log report of all the backup and recovery actions.
- Using RMAN you can backup whole database, tablespaces or datafiles.
- It provides the facility of incremental backup.
- It performs integrity check during backup.
- It helps in minimizing human errors.
User Managed backup
It uses user written shell scripts or operating system commands for performing backup. This backup strategy is manual process and does not have great features as RMAN that is why most people prefer RMAN.
Oracle Flashback technology
Oracle Flashback technology is like a time machine that let’s you view and rewind the past data without restoring the backup. Before Flashback, a database used to take long hours in recovering but now recovery time is reduced from hours to minutes. Flashback provides recovery at all level including row, table, transaction and whole database. It also allows you to undo the past changes. Some of the key features of flashback are:
- It allows you to perform queries on past data.
- It automatically repairs data in case of logical corruption.
- It provides point in time recovery of rows and tables.
- It also recovers all the data from a dropped table.
Oracle Flashback has the same functionality as of rollback command. It allows users to access the past state of data without performing point in time recovery. The command used to perform flashback is FLASHBACK DATABASE. This command undo all the changes performed by Oracle database in datafile. Flashback Database is a fast process because the time to perform flashback is depend on the number of changes that you have made in the database. Using this command user can also flashback their data to their desired point in time.
Data Recovery Advisor
It automatically detects corruption, data failure in a database and also provides repair options that are executed at user request. Data Recovery Advisor repairs Oracle block corruption, data dictionary corruption etc. It can be used through Enterprise Manager Database Control or RMAN command line. If Data Recovery Advisor integrity check detects failure then to repair the database you can use any repair option, automatic or manual.
Author Bio: Mansi Khurana is a professional blogger and love to write on various technologies.