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7/27/2019 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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