1 chapter overview understanding data restoration issues understanding the types of database backups...

1

Chapter Overview

• Understanding Data Restoration Issues

• Understanding the Types of Database Backups

• Understanding the Restoration Process

2

Data Restoration Goals

• Provide fault tolerance where possible.

• Monitor for problems before they occur.

• Plan for all forms of disasters.

• Determine acceptable data restoration times for each type of disaster.

• Quickly verify proper database functionality.

3

Types of Data Backups

Full database backup Differential database backup

Filegroup (or file) backup

Differential filegroup (or file) backup

Transaction log backup

Snapshot backup technology

4

Types of Data Restorations

Full database restore Filegroup (or file) restore with full recovery

Recovery to a point in time

Recovery to a named transaction

5

Databases to Back Up

• Applicable user databases

• The master system database

• The msdb system database

• The model system database, if this database has been customized

• The distribution system database, if replication is being used

6

Components of a Data Restoration Plan

• Document the entire system.

• Document the backup plan.

• Automate backups.

• Test the backup plan.

• Store backup media securely.

• Determine how long to retain backups.

7

Full Database Backups

• Complete copy of a database as of the end of the backup.

• Online backup with only a small impact on performance.

• Either a full database backup or a backup of all filegroups is the starting point for a database restoration.

• Perform after initial population of the database and periodically thereafter.

8

Differential Database Backups

• Complete copy of all database changes since the last full database backup

• Records only the most recent change

• Length of time required proportional to the number of modified extents

• Generally uses significantly less space than a full database backup

• Use with medium to large databases between full database backups

9

File and Filegroup Backups

F08vl01.FH8

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Differential File and Filegroup Backups

• Complete copy of all changes in file or filegroup since the last full file or filegroup backup

• Conceptually the same as differential database backups

• Use to back up frequently changing tables in between full file or filegroup backups

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Transaction Log Backups

• Sequential record of changes since the last transaction log backup.

• At the end of a transaction log backup, all VLFs containing inactive portions of the transaction log are truncated.

• Time and space required depends on frequency of changes to the database and frequency of transaction log backups.

• Frequency of transaction log backups depends on several factors.

12

Full Database Backup Strategy

13

Full Database and Transaction Log Backup Strategy

F08vl03.FH8

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Differential Backup Strategy

15

Database File or Filegroup Backup Strategy

16

Automatic Recovery Process

17

Recovery Process Using a Full Database Backup

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Recovery Process Using Filegroup (or File) Backups

19

Restoration and Recovery to Another Point in Time

20

Recovery Scenarios

• A user database data disk failure

• A user database transaction log disk failure

• A master database disk failure

21

Chapter Summary

• Develop, document, and test a data restoration strategy that anticipates all forms of disasters.

• Perform full database backups regularly, and use differential database backups between full backups to reduce recovery time.

• Perform frequent transaction log backups to provide redundancy and to truncate the transaction log.

• Use the Full Recovery model if point-in-time recovery or recovery to a specific mark is needed.