The fire in the survey office
A research team keeps a year of survey results on one computer. They copy it each week to a disk on the shelf beside it. One night a cable overheats and a fire starts in that room. The computer is gone. So is the disk.
The team did make a backup. It simply kept it in the wrong place.
Key words
| Word | What it means |
|---|---|
| Backup | a spare copy of data kept in case the original is lost |
| Restore | to copy data back from a backup |
| Onsite backup | a copy kept in the same building |
| Offsite backup | a copy kept in a different place |
| Cloud backup | a copy kept with an online provider |
| Recovery procedure | written steps to get systems and data back |
| Encryption | scrambling data so only the right people can read it |
| Bandwidth | how much data a link can carry each second |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can compare onsite, offsite and cloud backups and say what a recovery procedure holds.
Starter
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Starter
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Three places to keep a backup
An onsite backup is kept in the same building, on a disk or an external drive. It is quick to make and quick to restore. But a fire, flood or theft can take it with the original.
An offsite backup is kept somewhere else, such as another office. It survives a local disaster, but takes longer to bring back.
A cloud backup is kept with an online provider. It is offsite, with no site of your own to run.
Onsite, offsite and cloud compared
| Feature | Onsite | Offsite | Cloud |
|---|---|---|---|
| Where | Same building | Another site you own or rent | A provider's data centres |
| Speed to restore | Fast | Slower, as the copy must be fetched | Depends on bandwidth |
| Survives a fire or flood here? | No | Yes | Yes |
| Main cost | Disks and care | A second place and the trips | A fee each month |
| Main risk | Lost with the original | Lost in transit or stolen | Needs good encryption and a good provider |
The cells students fill in are left blank in this preview.
Check
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Check
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.