Backup Mechanism in Database

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PRESENTED

VIVEK JAISW


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BACKUP

The Process Of Periodically Taking A Copy Of The DataLog File On To Offline Storage Media.

In IT, A Backup, Or The Process Of Backing Up, Refers TCopying & Archiving Of Computer Data So It May Be U

Restore The Original After A Data Loss Event.


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Backup Process

Hot Backup

Cold Backup

Oracle Backup Option

Offline Physical BackupStorage media for Backup

Online Physical Backup

Logical Backup


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Hot Backup

Also called asDynamic Backup.

It is a backup performed on data even though it is actively ausers and may currently be in a state of being updated.

Hot backups can provide a convenient solution in multi-usbecause they do not require downtime.

Hot backups involve certain risks also if the data is altered wbackup is in progress, the resulting copy may not match theof the data.

If recovery of the data becomes necessary, the inconsistency

resolved.


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Hot Backup Purposes

Allows Backup Of The Database While The Database Is

And Available To Users.

Performance Degrades During The Backup Period.

Takes Longer Than A Cold Backup.


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Cold Backup

Also Called As Offline Backup.

Its A Database Backup When The Database Is Offline And TAccessible For Updating.

Its A Safest Way To Backup Because It Avoids The Risk Of CThat May Be In The Process Of Being Updated. However, A Involves Downtime Because Users Cannot Use The DatabasBeing Backed Up.


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Cold Backup


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Cold Backup Purpose

Requires Database Shutdown Before Backup Begins.

Physical Files Are Backed Up While Shutdown.

Database Is Unavailable To Users During Backup Perio

Faster Than A Hot Backup.


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Oracle Backup Options

Off-line Physical Backup Is A Cold Backup Technique

Copies Data Files, Log Files & Control Files After Shu

On-line Physical Backup Is A Hot Backup Technique

Temporarily Sets Table spaces Into Backup Mode Logical Backup

Is A Hot Backup Technique Exports All Or Part Of The Database By Creating SQL Script

Necessary To Recreate The Objects.


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Oracle Backup Options


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Off-line Physical Backup

Offline Physical BackupIt Is A Process Of Backing Physically On The Hard Drive Offline .

Shut down the database

Backup the data files

Backup the control files

Backup the online redo log files or the archive log fi

Backup the initialization and password files

Restart the database


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Storage Media For Backup

Magnetic TapeHard DiskOptical Storage

Solid State StorageRemote Backup ServiceFloppy Disk


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On-line Physical Backup

Requires The DB To Be In Archive Log Mode

For Each Tables pace Set The Table space Into A Backup State Backup The Data files For That Table space Restore The Table space To Its Normal State


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On-line Physical Backup

Backup The Archived Redo Log Files Stop The Archiving Process Note Which Files Are In The Arch Log Directory Restart The Archiving Process Backup The Archived Redo Log Files

Delete The Archived Redo Log Files Backup The Control File Using The Alter Database

Backup Control file Command

Backup The Initialization And Password Files


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Logical Backup

Essentially Creates SQL Scripts That Will Recreate Data Use Oracle Export Utility To Create .Dmp File

Use Oracle Import Utility To Selectively Import DatabaFrom The .Dmp File

Can Perform Complete Database Backup User (Schema) Backup Individual Table Backup

Used In Conjunction With A Recovery Server To RecovObjects (Not Entire Database)


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Backup Types

Complete (Full) Copy All Database And Related Files Delete The Archive Log Files

Cumulative (Differential) Copy Blocks That Have Changed Since Last Full Backup

Or Copy All Archive Log Files Generated Since Last Full Backup

Incremental Copy Blocks That Have Change Since The Last Partial Backup

Or Copy All Log Files Generated Since Last Partial Backup

Complete (Copy) Copy All Target Data Dont Include The Set In Backup Set Logic


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Documents

Backup Mechanism in Database