Backup and Recovery

Topic Six

How many of you have ever lost work on a computer?

How often do you back up your work or PC or laptop?

Threats to ICT Systems• Computer/hardware failure• Deliberate damage• Accidental damage• Theft• Hacking• Fire• Terrorist attack• Natural disasters• Viruses• Software bugs• Power cuts

Malpractice and Crime

•Malpractice – improper, careless or unprofessional conduct

•Crime – illegal act, punishable by law, contravention of a law

Viruses

• Main threat from malicious damage• Program that replicates itself and

infects computers.• Usually carries with it a payload that

causes damage– Annoying messages– Delete programs or data– Use up resources and slow down

running

Viruses• On the internet find out the names

and ‘modus operandi’ of three different types of virus.

• Viruses take time and resources to get rid of.

• Trojans – performs a legitimate task but also has an undesirable function

• Worm – keeps replicating itself using more resources up

Viruses

• Spread by– Email (commonly attachments)– Intranet– Shared disks– Banner adverts– Downloads

Preventing Viruses• Install virus checking software• Do not open emails from unknown sources• Do not open file attachments unless from

a known source• Keep software up to date• Have an AUP• Train staff to be aware of problems• Do not allow programs such as games etc• Prevent use of user removable media if

possible

The Importance of Backup• Backup procedures• Copies taken regularly on a routine

basis• Copies kept away from the computer

system• Copies could be kept in a fireproof

safe• Copies preferably kept off site

Online Backup Services

• Advantage is the procedure can be automated

• Backup is off site on a separate server• Data is encrypted before sending to

prevent security problems• Disadvantage is trust and cost• www.datadepositbox.com/democitytv.

asp

Backup Procedures

• Use a different tape/disk each day and rotate them

• Make one person responsible• Keep backups safe• Rehearse recovery procedure

Scheduling Backups

• Backing up uses system resources so system will slow down

• Backups can be manual or automatically scheduled

• Use of ancestral file system (3 generations)

• Full backup and partial (transaction) backup

The Needs of Individuals

• Backup strategy– What– When– How– Storage

What

• Types of backup– Full backup– Incremental backup– Differential backup (cumulative)– Continual backup (mirrored disks)

When

• Dependant upon how much data changes and how often it changes

• Individuals• Organisations

– Systematic– Often in the evening

How

• Wide variety of storage media• Depends upon

– Storage capacity– Portability– Speed of data transfer– Speed of access– Requirement to be connected to

different devices

Backup Media

• Magnetic tape (cheap and removable)

• Magnetic disk (simple)• Optical media (slow transfer

rate)• Pen/flash drives (small storage)• Floppy disks – no more!

Responsibility for Backups

• Why is this needed?• Recovery procedures

– Alternative accommodation– Availability of staff at short notice to

recover backups– Availability of hardware to run backups– Training for staff on recovery procedures– Alternative communication lines

Continuity of Service

• Dual processing• RAID systems• Clustering• Examples of organisations

needing continuity of service?

Homework

• Case Study 1 on page 215 of your text book.

• Please have ready to hand in first lesson after the half term.