2.6 backup and recovery

INFO 22.6 Backup and Recovery

Print out Scary backup stories

Prior

1. What 6 questions should you ask yourself before writing a backup strategy?

2. When devising a backup strategy, risk assessment should be carried out, what should be looked at during this process?

3. What effect would it have on an organisation if they lost their data?4. What 4 types of backup can be performed?5. Describe a Full backup6. Describe a differential backup7. Describe an incremental backup8. In order to make sure backups work what should you do?9. What types of media could be used to backup systems?10. What is meant by continuity of service and why is it important?11. What is RAID12. What is DRP and what does it aim to do?13. What is backup strategy? 14. When choosing backup media and devices what factors should be

taken into consideration?

To consolidate you should be able to answer these questions…

Specification

Do you backup your work? What work do you backup? When do you back it up? How do you backup your work? Which media do you use to backup your work? Why do you back up your work?

Different individuals and organisations have different backup needs but they will all ask the same questions

http://ictknowledgebase.org.uk/backupstrategy

Backup

Read and discuss the stories

What 3 things must you do in order for backups to work?◦ Define and implement a good procedure◦ Test that it works◦ Review your procedure often

Scary Backup Stories

I asked you these questions:◦ What work do you backup?◦ When do you back it up?◦ How do you backup your work?◦ Which media do you use to backup your work?

Organisations will also need to ask these two questions:◦ Who will be responsible for the backup◦ Where will the data be stored

Establishing the answers to these questions will allow the organisation to develop a Backup Strategy*

Backup…A couple of other questions

1. Assess what risks apply to the data2. How likely it is that the hazards creating

those risks will take place3. What effect would it have on the organisation

if that hazard occurred?

For some organisations their ICT systems is mission critical (They cannot operate without it)

If EasyJet’s booking system went down for more than 48hrs they would go bankrupt

The person responsible for backup must:

2%

32%

25%

22%

13%6%

Causes of Lost DataNatural Disasters

Human Error

Software Corruption

Virus Attack

Hardware Error

Sabotage

What risks do apply to the data?

Must conduct thorough analysis

Must be monitored ◦ e.g. signing up for e-mails or alerts from local

weather stations so that you are made aware of impending weather events

How likely is it that the hazards creating those risks will take place?

Damage to reputation Damaged loyalty

◦ i.e. customers may defect to a competitor Loss of labour Loss of revenue Loss of service

What effect would it have on the organisation if that hazard occurred?

http://goo.gl/Nlxl5

On average, businesses lose between $84,000 and $108,000 (US) for every hour of IT system downtime, according to estimates from studies and surveys performed by IT industry analyst firms.

It is critical that organisations can recover quickly

*Discussed later on under ‘continuity of service’

Assessing the Financial Impact of Downtime

A recent study has shown that of the companies that lose their data in a disaster:

29% are out of business within two years

Nearly 43% never open their doors after the disaster

Other statistics

Backup – real life incidents

Backup – real life incidents

As you can see backing up data is important. Most organisations will have a backup strategy in place to support their data protection and recovery.

A strategy is simply a plan of action designed to achieve an overall aim

A backup strategy therefore is a planned approach to data protection and data recovery

Policies/Procedures are written to support implementation of the strategy

◦ A Policy/Procedure might be “a full backup must be performed every night”

Backup Strategy*

◦ What work do you backup?◦ When do you back it up?

◦How do you backup your work?

◦ Which media do you use to backup your work?◦ Who will be responsible for the backup◦ Where will the data be stored

You have choices as to HOW you backup your work

Remember these questions?

Full Backup◦ All the data that is stored in your files or folders that you wish to

back up will be saved.

Advantages◦ EVERYTHING is backed up at once on one device◦ Restoring the data can be a simple process◦ Data can better protected

Disadvantages◦ Can take a long time to run the backup (depending on quantity of

data)◦ Can take a long time to restore the back up◦ Storage media and medium for a FULL backup could be expensive◦ Security issue as each full backup contains an entire copy of all data

How can data be backed up?

Differential Backup◦ Only the data that is different since the last FULL backup

will be saved

Advantages◦ Reduces the time it takes to restore data◦ Usually an automatic process◦ Only the full and differential backup are needed to restore the

data

Disadvantages◦ If to many differential backups are performed size of the

backup can be larger than full backup◦ Slower than an incremental backup

How can data be backed up?

Incremental Backup◦ Saves all the files that have been changed since

the last backup (NOT just the last FULL backup)

Advantages◦ Fastest way to backup◦ Usually an automatic process

Disadvantages◦ Restoring data can take a long time

How can data be backed up?

Full Backup◦ All the data that is stored in your files or folders that you wish to

back up will be saved.

Differential Backup◦ Only the data that is different since the last FULL backup will be

saved

Incremental Backup◦ Saves all the files that have been changed since the last backup

(NOT just the last FULL backup)

Here’s a video to help illustrate the difference between an incremental backup and a differential backup: http://goo.gl/3hyG3

How can data be backed up?

Refers to backup of computer data by automatically saving a copy of every change made to that data

Essentially capturing every version of the data that the user saves.

Advantages◦ It allows the user or administrator to restore data to any point in time◦ In some situations, continuous data protection will require less space on backup

media (usually disk) than traditional backup. Most continuous data protection solutions save byte or block-level differences rather

than file-level differences. This means that if you change one byte of a 100 GB file, only the changed byte or block is backed up

Disadvantages◦ The continuous bandwidth usage can adversely affect network performance,

especially in operations where file sizes are large, such as multimedia and CAD design environments. To mitigate this risk, companies employ throttling techniques which prioritize network

traffic in order to reduce the impact of backup on day-to-day operation

Continuous data protection / continuous backup

Some solutions which are marketed as continuous data protection may only allow restores at fixed intervals such as 1 hour, or 24 hours.

Such schemes are not universally recognized as true continuous data protection, as they do not provide the ability to restore to any point in time.

Such solutions are often based on periodical snapshots,

Continuous vs near continuous

There is a popular backup method called the Grandfather, Father, Son backup

Homework 1◦ Research the Grandfather, Father, Son backup

method and create a resource to illustrate this process

http://www.lockergnome.com/it/2005/04/18/gfs-backup-strategy/

Other backup Methods

◦ What work do you backup?◦ When do you back it up?◦ How do you backup your work?

◦Which media do you use to backup your work?

◦ Who will be responsible for the backup◦ Where will the data be stored

You have choices as to WHICH media you backup your work on

Remember these questions?

Dependant on:◦ Storage capacity required◦ Portability of device◦ Speed of data transfer◦ Speed of access (time it takes for device to find a

specific piece of stored data

Choice of backup devices

Magnetic Tape Hard disks Optical disks e.g. CD, DVD Remote Backup service e.g. online backup Flash Memory

Homework 2◦ Create a PowerPoint presentation with 6 slides◦ Slide 1 called Backup media◦ Slide 2-6 titles are those above (e.g. Magnetic Tape)◦ On slides 2-6 introduce the media (include a picture) and

then highlight advantages and disadvantages of using that media e.g. cost storage capacity, speed etc.

Optional storage devices

Have you ever had to recover your work? What procedures did you go through in

order to recover your work?

Remember recovery (like backup) should be:◦ Planned◦ Checked i.e. checked people understand◦ Tested i.e. checking the recovery

Recovery

Organisations need recovery procedures

These procedures are put in place to get the ICT system working again

Procedures considered include:◦ Alternative accommodation◦ Availability of step to help recovery process◦ Availability of hardware to run the backups◦ Training◦ Availability of alternative communication lines

Recovery Procedures

Many companies rely on 24/7 service in order to function (e.g. online booking systems).

Failure to do so could have financial consequences as well as customer dissatisfaction.

Policies are required to ensure this happens, should cover:◦ Location of backup◦ Security of backup◦ Appropriate backup for continuous service e.g.

RAID

*Continuity of service

Redundant Array of Independent Disks

RAID 1 – Mirroring◦ Mirror the drives◦ Exact copy

RAID 5 – Distributed Parity◦ Strips the data across all 5 drives◦ Can survive on two drives

RAID

What is DRP and what does it aim to do? Disaster Recovery Plan

Tries to ensure that businesses can:◦ Resume trading quickly by ensuring ICT services

are back online as soon as possible◦ Give customer, investors and trading partners

confidence in the reliability of the company◦ Retain customers who might change companies if

there is a loss in trading time

Half the class◦ Research the Grandfather, Father, Son backup

method and create a resource to illustrate this process

Other half◦ Create a PowerPoint presentation with 6 slides◦ Slide 1 called Backup media◦ Slide 2-6 titles are those above (e.g. Magnetic Tape)◦ On slides 2-6 introduce the media (include a picture)

and then highlight advantages and disadvantages of using that media e.g. cost storage capacity, speed etc

Homework

Past Paper Questions

Past Paper Questions

Past Paper Questions

Page 99 and 100 of the McNee and Spencer Text Book.

Read both Case Studies and answer the ‘End of sub-Topic Questions’ 4, 5 and 6 (Page 100)

For tomorrow’s lesson (This must be printed out prior to lesson NOT on your arrival to the lesson)

◦ Thursday detention if failure to complete OR failure to have printed out before the lesson

Homework