Friday at 4 pm
A small firm keeps its orders on one server. At 4 pm on Friday the disk fails. The last copy was made on Monday.
Four days of orders are gone. The firm now has to ask every customer to order again.
A good back-up plan would have made that a ten minute job.
Key words
| Word | What it means |
|---|---|
| Back-up | An up-to-date copy of data kept so it can be restored later. |
| Restore | Putting data back from a back-up. |
| Disaster recovery | Getting a whole system working again after a big failure. |
| Frequency | How often a back-up is made. |
| Source | What is copied: which files or data. |
| Destination | Where the copy goes: inside the site or outside it. |
| LTO | Linear tape open: a standard tape cartridge for long term storage. |
| Ransomware | Software that locks your data and demands money to unlock it. |
| Cloud | Storage on servers run by another company and reached over the internet. |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can say why a business makes back-ups and choose the frequency, source, destination and storage for a plan.
Starter: what you know
Have a go
Starter: what you know
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Cycle 1: the purpose
The purpose of a back-up is to keep an up-to-date copy of data so it can be restored in future.
Two sizes of problem:
- Partial loss: one file is deleted or damaged. You restore that file.
- Full disaster recovery: a fire, a flood or ransomware takes the whole system. You restore everything.
The core security course explains why back-ups matter. This lesson is about planning one.
Cycle 2: four things to decide
A back-up plan answers four questions.
- Frequency: how often? Hourly, daily or weekly. This is a periodic back-up.
- Source: what? Files, or other data such as customer records. Copy what is hard to replace.
- Destination: where to? Internal (the same site) or external (another site).
- Storage: on what? LTO tape, cloud or disk.
Worked example: three kinds of storage
| Storage | Good for | Watch out for |
|---|---|---|
| LTO tape | Cheap, long term, can be taken off site | Slower to restore |
| Cloud | Off site with no one to carry it | Needs the internet and a monthly cost |
| Disk | Fast restore | A fire can destroy it and the original together |
The cells students fill in are left blank in this preview.
Check: the four decisions
Have a go
Check: the four decisions
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.