Oracle Backup and Recovery (v)

Backup:
Defined:
The process of copying a database to a dump device.
Dump device:
The tape or disk where the database copy is placed.
Backup of the original database:
A copy of the database stored in a dump device.

Classification:
Physical and logical angles:
Physical Backup:
A backup of the physical files (data files, control files, log files) of the database.
Divided into:
Offline backup (cold backup):
You must close the database.
Online backup (hot backup):
Back up the running database as an archive log.

Recovery Manager (RMAN) available with Oracle
or operating system commands for physical backups.

Logical Backup:
A backup of database logical components (database objects such as tables, stored procedures, and so on).
EXP, Data Pump (EXPDP), database flashback technology and other third-party tools backup.


Database backup angle:
Full backup:
Complete backup of the database for 100% data recovery.
The shortest recovery time and the most convenient operation.

Incremental backup:
Files that were modified after the last full or incremental backup are not backed up.
Advantages:
The amount of backup data is small and time is short.
Disadvantages:
Restore relies on previous backup records. Greater risk.

Differential backup:
Backs up files that have been modified since the last full backup. The recovery time is relatively short.
Two data required:
Last full backup.
Last differential backup.
Disadvantages:
Each backup takes longer.


Recovery:
Defined:
Once a failure occurs, the full database is re-established using the backed up data file or control file.
Classification:
Instance recovery:
Instance fails and Oracle recovers itself.
Media Recovery:
The recovery that holds the database media in the event of a failure.
Divided into:
Full recovery:
Revert to the state before the data failed.
Do this by loading the database backup and applying the full redo log.
Not fully recovered:
Reverts to the state of a time before a database failure.
done by loading a database backup and applying a partial redo log.
Reset the online redo log with the Resetlogs option when starting the database.



Using the Rman tool:
Storage type:
Backup set
Compress backup Sets
Mirror copy

Backup slices:
Each file that makes up each backup set

Rman Backup storage location (2):
Control files for the target database
The recovery directory.

Rman Backup Benefits:
Rman backs up only valid data
Rman enables incremental backups.

Role:
Backup and restore data files, archive logs, control files.

Perform a full or incomplete database recovery.

3 different types of user interfaces:
command-line mode,
GUI Mode (Backup manager)
API mode (integrated into backup software)
Characteristics:
Support Online hot backup.
Supports multilevel incremental backups.
Supports parallel backup and recovery.
Reduce the amount of backup required.
Back up, easy to use recovery.



Rman components:
Target database:
Rman is required to back up and restore it.

Service session (server session)
Rman starts the Oracle server process on the database,

A dialogue with the target database will be established.

Rman Repository (Rman repository):
Control information that is used by Rman during use.

Recovery Catalog (recover catalog):
A schema object that is built on the rman recovery catalog database

Used to save Rman repository data.
It is recommended that you create a recovery directory in a separate database and save a copy of the repository data.


MML (Media Management Library):
Manage the read-write and file tracking management of tapes.

Media management tools work with Rman to complete backup and recovery.

Quick Flash Recovery zone:
Save the default disk location for all recovery-related files. Includes archive logs, Rman backup,

Control file automatic backup, reuse of control files and redo log copies and flashback log files.

Secondary database:
Use Rman to create a new database from a backup of the target database.
Available as a standby database.


To create a recovery directory:
exists in the catalog database of Rman.
Information that contains the following sections:
Backup recovery information.
Rman scripts, which can be used for storage reuse.
Backup information for data files and log files.
Table space and data file information for the target database.

The Rman repository can be stored in the target database control file or in the recovery directory.

This article is from the "Enron Smile" blog, please be sure to keep this source http://liyuanjie.blog.51cto.com/12877605/1963973

Oracle Backup and Recovery (v)