2-14 Backup and Recovery

A backup is simply an extra copy of data. So if data becomes corrupt or lost/stolen, it can be recovered.

A backup a recovery strategy is vital within any organisation.

Companies that have large data loss, 6% survive

Data could be:
        - Stolen 6%
        - Lost to diasaster 2%
        - Human error 32%
        - Hardware + Software error 38%

Backup media (storage)
        - USB Stick
        - CD and DVD
        - External Hard Drive

Organisations commonly backup to large hard drives in another remote location.

RAID Systems - instant backups in real time. Basically a massive amount of cheap hard drives that instantly copy the data.

DAT tapes - Removable media with a large capacity. Now surpassed by hard drives

Cloud - Remote backing up of data via the internet. The cloud is a concept and made up of various hard drives across the globe Eg. a word document sent to your own e-mail is store in the "cloud"; accessable from anywhere in the world. If you deleted it from all computers, it would still be avaliable from the internet

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Backup Strategy

What files should be backed up?
Who is resposible?
When will the backups be done?
Where will the backups be kept?
Which backupmedia will be used?

Recovery Strategy

What files, OS and software/applications will need to be recovered?
Who is resposible?
When will the deadlines for recovery be?
Where are recovery offices and computer equiptment
How will we ensure continuity of service

Types of Backup
Type of Backup	Time to Backup	Full Restoration Time	Storage Space
Full – All data is backed up.	A long time as all data is saved.	Very fast as a full restore is complete in one go.	Very large size commonly stored on a removable hard drive.
Differential – Data that has changed since the last full backup.	A medium amount of time as a large group of data is saved.	A medium amount of time as a full restoration would be done in a few large chucks.	A medium size stored either on a large memory stick or a DVD
Incremental – Data that has changed since any other backup.	A short amount of time as small files and documents are saved.	A very long time as a full restoration would be done in very small amounts at a time.	The smallest with only a few files on a small USB stick