Backup and Recovery Strategies

7/29/2019 Backup and Recovery Strategies

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BUSINESS SYSTEM

MANAGEMENTTOPIC 11

DISCUSS BACKUP AND RECOVERY

STRATEGIES


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LESSON CONTENT

Introduction

Why backup

Backup location

What data should be backed up

What should you backup onto

Backup procedures


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Introduction

Everyone who uses a computer tosave or store files will at some time or

another experience that heart stopping

moment when they realize their filesare lost.


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Why Backup?

Every day individuals, businesses,and organizations lose their precious

files due to a

drive failure, inadvertent deletion, or other unwanted

action or event.

The result is a great deal of stress,anxiety, and in the case of businesses,

lost revenue.


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Why Backup?

The computer hard drive that stores allyour data has moving parts, and in

time your hard drive will wear out and

fail. It's just a matter of when. You need to

keep a copy of all your important data

somewhere else.


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Major causes of system

errors: Human act

Natural act

Technical


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Major causes of system

errors: Human act ( error, labor unrest,

erasure of an important file)

Information system personnel

Authorized user Non authorized users


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Natural act

Wind

Fire

Earthquake

Extreme temperature

Floods

Hurricane


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Technical

Hardware

Application software

Systems software (refers to the files andprograms that make up your

computer's operating system. installed on

your computer when you install your

operating system.)

Communication

Electricity


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Backup Location

You need to store a copy of all your importantfiles in a different location to where yourcomputer is situated.

It's not a great deal of use having the copy ofyour files on your external hard drive which isconstantly plugged into your computer.

A thief won't leave your additional drive foryou to recover your lost files, a fire or floodwon't distinguish between your computer and

your external drive. At the very least, keep your copy in a different

location in your home. If possible, keep yourbackup copy in an entirely different building.


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Backup Location

Some choose to

backup their data

onto remote

servers via FileTransfer Protocol

(FTP)

Others use the

services of off-sitebackup over the

Internet.


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What Data Should Be Backed

Up? pictures, videos, music, Microsoft Office documents, spreadsheets,

databases,

Internet Explorer Favorites and/or Firefox

bookmarks, emails etc, keep a copy of all the programs you use so

that if necessary they may be easilyreinstalled at a later date.

It would be advisable therefore to copy anynew programs you download and install themfrom the Internet in a special folder that getsbacked up as part of your backup routine.


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Up? One especially important program to

backup is the program you use for the

backup procedure itself.

You'll also need to save the serialnumber for this program and others in

a secure yet memorable location so

you can restore your backup to theoriginal location at a later date should

you need to.


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Up? If you use your computer for business

purposes you will also need to backup

all the information from your

financial software, inventory control,

customer databases,

and other specialist business files.


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What Should You Backup

Onto? There are many different types of

media that you may choose to backup

onto, and each has their own

advantages and disadvantages. Thefirst thing you'll have to work out is

what suits your particular

circumstance


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Onto? It's generally a good idea to choose

media that allows you to backup all

the data you wish to without having to

'span' the backup. For example, you may need many CDRs

to backup all your information.

The problem with this kind of backup isthat it requires your intervention to replace

the new media as each disk is required


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Onto?A backup that can automatically run

without your intervention will save you

a great deal of time over the long run.

An external USB hard drive for examplecan plug straight into a computer and

provide an instant large capacity space for

your backups.


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Backup procedure

Business and homes users canperform four types of backup.

Full

Differential Incremental

Selective

Continuous data protection CDP(typically is used only by large

enterprise)


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Full backup

Sometimes called an archival back up

Copies all of the files in the computers

Provides the best protection against

data loss because it copies allprogram and data files.

Performing a full back up can be time

consuming


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Differential backup

Copies only the files that havechanged since the last full backup

Then creates copies of all the files that

are different from the ones in the fullbackup.


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Example:

Let us take for example that you aretaking a full backup of a folder 'TestFolder'

containing Four files File A, File B, File C and File D on day 1

and have scheduled to take differentialbackups of the folder on a daily basis.

The following table explains what wouldbe the contents of successive differentialbackups, if you modify the files as given incolumn two.


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DayFiles

EditedType of

Backup

takenFiles contained in

the full backup

(Test

Folder_full_files.cb

u)

Files contained in the

differential backup (Test

Folder_dif_files.cbu)

Day 1 Full File A, File B, File Cand File D

Day 2 File A Differential File A, File B, File Cand File D (originalversions)

File A (modified version)

Day 3 File B Differential File A, File B, File Cand File D (original

versions)File A (version modified on

Day 2) and File B (version

modified on Day 3)

Day 4 File Band File

CDifferential File A, File B, File C

and File D (original

versions)File A (version modified on

Day 2), File B (version

modified on Day 4) and File

C (version modified on Day

4)


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Incremental backup

Copies only the files that have beenchanged since the last or lastincremental backup.

With incremental backup, you have thefull backup and one or more incrementalbackups.

The first incremental backup contains

changes since the last full backup. Each subsequent incremental backup

contains changes only since the previousincremental backup


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Example:

Let us take for example that you aretaking a full backup of a folder 'TestFolder'

containing Four files File A, File B, File C and File D on day 1

and have scheduled to take incrementalbackups of the folder on a daily basis.

The following table explains what wouldbe the contents of successive incrementalbackups, if you modify the files as given incolumn two.


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Day FilesEdited

Type of Backup

takenFiles contained in the full

backup (Test

Folder_full_files.cbu)

Files contained in

the incremental

backup (TestFolder_inc_files.cb

u)Day 1 Full File A, File B, File C and File D

Day 2 File A Incremental File A, File B, File C and File D(original versions)

File A (modified

version)

Day 3 File B Incremental File A, File B, File C and File D(original versions)

File B (modified

version)

Day 4 File Band File

CIncremental File A, File B, File C and File D

(original versions)File B (version

modified on Day 4)

and File C (version

modified on Day 4)


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Selective backup

Sometimes called partial backup

Allows the user to choose specific files

to back up, regardless of whether or

not the files have changed since thelast incremental backup.


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Continuous data protection

(CDP) Sometimes called Continuous backup Backup plan in which all data is backed

up whenever a change is made Because CDP is costly, few organisation

have implemented CDP, its popularity isgrowing quickly as the cost for thistechnology is falls.

CDP require little or no maintenance

where compared to other backupmethod. Many experts believes that CDP will

replace all other types of backup in the

future


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Backup Procedures

Continuous data protection providesautomatic data backup whenever data

is changed in an enterprise


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Backup procedures

Specify a regular plan of copying andstoring important data and program

files.

Generally, users should perform fullbackup at regular intervals, such as

at the end of the week and

at the end of the month

Between full backup, you can perform

differential and incremental backup.


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Backup procedures

Whatever backup procedures acompany adopts, they should be:

Stated clearly

Documented in writing Followed consistently


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Disaster recovery plan

A disaster recovery planis a writtenplan describing the steps a company

would take to restore computer

operations in the event of a disaster Contains four major components

Emergencyplan

Backupplan

Recoveryplan Test plan


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The emergency plan

Specifies the steps to be takenimmediately after a disaster strikes

The emergency plan usually is

organized by type of disaster, such asfire, flood, earthquake.

Depending on the nature and extent of

the disaster, the procedures that arefollowed in emergency will differ.


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The emergency plan

All emergency plans should contain thefollowing information: Names and telephone numbers of people

and organisation to notify ( eg. Management,

fire department, police department) Procedure to follow with the computer

equipment (e.g. equipment shutdown, powershutoff, file removal)

Employee evacuation procedures Return procedure that is who can reenter the

facility and what action they are to perform.


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The backup plan

Once the procedures in the emergencyplan have been executed, the next stepis to follow the back plan.

The backup plan specifies how anorganisation uses backup files andequipment to resume informationprocessing.

The backup plan should specify thelocation of an alternate computer facilityin the event the organizations normallocation is destroyed or unusable.


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The backup plan

When operations are so important thatthe organisation cannot afford to lose theoperation to a disaster, the organisationoften maintain a HOT SITE, which is a

separate facility that mirrors the systemsand operations of the critical site

The hot site always operate concurrently(Operating or acting in conjunction withanother.) with the main site, so that ifeither site become unavailable, the othersite continues to meet the organisations

needs


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The backup plan

The process of one systemautomatically taking the place of afailed system is called FAILOVER.

COLD SITE is a site that mirrors thecritical site, but does not becomeoperational until the critical sitebecomes unavailable.

When using a COLD SITE, some timeelapses between the disaster andwhen the cold site become functional.


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The backup plan

The backup plan identifies theseitems:

The location of backup data, supplies and

equipment The personnel responsible for gathering

backup resources and transporting them

to the alternate computer facility

A schedule indicating the order in which,

and approximate time by which each

application should be up and running


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The backup plan

For a backup plan to be successful,the organisation must backup all

critical resources

Also, additional people, includingpossible nonemployees, must be

trained in the backup and recovery

procedures because personnel couldbe injured in a disaster.


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The backup plan

The location of the alternate computerfacility is important.

It should be close enough to be

convenient, yet not so close that asingle disaster, such as earthquake

could destroy both the main and

alternate computer facilities


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The backup plan

Some organisation preinstall all thenecessary hardware, software andcommunication devices at thealternate computer facility.

These facilities immediately are readyin event of a disaster.

In other cases, the alternate computer

facility is simply an empty facility thatcan accommodate the necessarycomputer resources if needed.


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The backup plan

One more alternate computer is toenter into a RECIPROCAL BACKUP

RELATIONSHIP with another firm,

where one firm provides space andsometimes equipment to the other in

case of disaster.


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Recovery plan

Specifies the actions to be taken torestore full information processing

operations.

As with emergency plan, the recoveryplan differ for each type of disaster.

To prepare for disaster recovery, an

organisation should establishPLANNING COMMITTEES, with each

one responsible for different forms of

recovery.


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Recovery plan

For example, one committee is incharge of hardware replacement,

another is responsible for software

replacement.


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The Test Plan

Provide assurance that the disasterplan is complete, it should be tested

Disaster recovery test plan contains

information for simulating various levelof disasters and recording an

organisations ability to recover.


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The Test Plan

In a simulation, all personnel followthe steps in the disaster recovery plan.

Any needed recovery action that are

not specified in the plan should beadded.

Although simulation can be scheduled,

the best test of the plan is to stimulatea disaster without advance notice.


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In summary

Why is computer backup is important,and how is it accomplished?

What are the steps in a disaster

recovery plan?


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Documents

Backup and Recovery Strategies