The back-up nobody ever tried
A firm had a back-up for three years. Every night it ran. One day the main disk failed.
They went to restore. The back-up files were empty. The job had been failing since the first week, and nobody had looked.
A back-up you have never restored is only a hope.
Key words
| Word | What it means |
|---|---|
| Back-up | a copy of data kept so it can be restored after a loss |
| Policy | a written rule saying what is done, how often and by whom |
| Procedure | the steps a person follows to carry out a policy |
| Full back-up | a copy of everything |
| Incremental | a back-up of only what changed since the last back-up of any kind |
| Differential | a back-up of everything that changed since the last full back-up |
| Restore | to copy data back from a back-up |
| Retention | how long back-ups are kept before they are deleted |
| Schedule | the times a job runs by itself |
| Database | an organised store of records that programs can search and change |
| Off-site | kept in a different place from the original |
The cells students fill in are left blank in this preview.
By the end of this lesson
Note
I can write a simple back-up policy, run and schedule a back-up, and prove that a restore works.
Starter
Have a go
Starter
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
What a back-up policy says
| Question | An example answer |
|---|---|
| What is backed up? | The shared projects folder and the college database |
| How often? | A full copy on Sunday, a daily change copy on the other days |
| Where is it kept? | One copy on a second disk, one copy off-site |
| How long is it kept? | Four weeks of copies, then the oldest is deleted |
| Who checks it? | The technician reads the log each morning and tests a restore each month |
The cells students fill in are left blank in this preview.
The 3-2-1 rule
Keep 3 copies of your data. The original counts as one.
Keep them on 2 kinds of storage, such as a disk and a cloud store.
Keep 1 copy off-site. A fire or a flood in the building cannot reach it.
A real back-up job
The linux-admin lab has a shared folder, /srv/projects, and a small back-up script. Press Start the lab.
First put two files in the folder. Then run the script.
Make two files to protect
echo "essay v1" | sudo tee /srv/projects/essay.txt && echo "plan v1" | sudo tee /srv/projects/plan.txtA command for the lesson’s lab terminal. It is shown here and not run.