Benefits of RMAN

The following table lists a comparison between the Oracle Recovery Manager (RMAN) and user-managed methods. Recovery Manager User-managed method Uses a media management API so that RMAN works seamlessly with third-party media management software. More than 20 vendors support the API. Does not have support of a published API. When backing up online files, RMAN rereads fractured data blocks to get a consistent read. You do not need to place online tablespaces in backup mode when performing backups. Requires placing online tablespaces in backup mode before backing them up and then taking the tablespaces out of this mode after the backup is complete. Serious database performance and manageability problems can occur if you neglect to take tablespaces out of backup mode after an online backup is complete. Performs incremental backups, which back up only those data blocks that changed after a previous backup. You can recover the database using incremental backups, which means that you can recover a NOARCHIVELOG database. However, you can only take incremental backups of a NOARCHIVELOG database after a consistent shutdown. Backs up all blocks, not just the changed blocks. Does not allow you to recover a NOARCHIVELOG database. Computes checksums for each block during a backup and checks for corrupt blocks when backing up or restoring. Many of the integrity checks that are normally performed when executing SQL are also performed when backing up or restoring. Does not provide error checking. Omits never-used blocks from data file backups so that only data blocks that have been written to are included in a backup. Includes all data blocks, regardless of whether they contain data. Stores RMAN scripts in the recovery catalog. Requires storage and maintenance of operating system-based scripts. Allows you to easily create a duplicate of the production database for testing purposes or easily create or back up a standby database. Requires you to follow a complicated procedure when creating a test or standby database. Performs checks to determine whether backups on disk or in the media catalog are still available. Requires you to locate and test backups manually. Performs automatic parallelization of backup and restore operations. Requires you to parallelize manually by determining which files you need to back up and then issuing operating system commands in parallel. Tests whether files can be backed up or restored without actually performing the backup or restore. Requires you to actually restore backup files before you can perform a trial recovery of the backups. Performs archived log failover automatically. If RMAN discovers a corrupt or missing log during a backup, it considers all logs and log copies listed in the repository as alternative candidates for the backup. Cannot fail over to an alternative archived log if the backup encounters a problem. Uses the repository to report on crucial information, including: Database schema at a specified time. Files requiring backup. Files that have not been backed up in a specified number of days. Backups that can be deleted because they are redundant or cannot be used for recovery. Current RMAN persistent settings Does not include any reporting functionality.