Backup and Recovery in Oracle Database
Although the backup Oracle database may be time-consuming, but the fear of loss than the transaction, revenue loss and customer dissatisfaction, this time-consuming and the insignificant. Therefore, the backup Oracle database in today is becoming a backup / storage administrator can do the most important task.
Users can look at a few common Oracle backup problems.
First of all, back up the Oracle database, including not only the physical data backup (a copy of the database files), but also the backup logical data --- data with the SQL command to export and in the redo log files in the cache that has been submitted and not submitted changes.
When the oracle database failure, the need to restore the relevant database files.
Recovery operations need to use the redo data will be updated to a new backup point in time, and the database transaction does not roll back to a consistent state before its error-free.
If the database or IT system administrators are already using a database snapshot, then the recovery may only need to use the snapshot and the application of redo data.
In the Oracle database backup, there are many files need a backup. They are data files, control files, online redo log files and archived redo log files. Oracle database is organized into one or more physical files, they are logically referred to as the table space. The data file itself is divided into data blocks. Control file contains the database name, create timestamp, data files, redo log files, a checkpoint and backup metadata. Redo log file records all changes to the database.
Each database has a mechanism to roll back and undo changes, changes for the containment and elimination. In Oracle, this is called the automatic management of undo. Undo records will help roll back the transaction operation, data recovery and read consistency.
Oracle provides a number of ways to back up the database. Including Recovery Manager (RMAN), enables automated backup and recovery operations; Oracle Data Pump to the logical database backup; and user management, user management allows the user the operating system command to manually back up the database.
At the same time there are a variety of other database backup and recovery software, and enhanced Oracle backup utility, such as CommVault's Simpana and IBM's Tivoli Storage Manager.
Oracle Backup Tips
Here are some of the useful from the experts, Oracle database backup best practices, including:
1. When the database is running when the hot backup, do not back up the active transaction;
2. The use of tools such as Oracle or other third-party software compression Oracle backup data, such as IBM / Tivoli Data Storage Manager. For example, using Oracle RAMN, database table compression can scan large tables full time reduced by half.