Incremental backup

Name:

Date:

Class:

Quick Questions

Shade in the A or B circle for each question.

1. An incremental backup copies only the files changed since...

A the last backup of any type (full or incremental)

B the last full backup only

2. Compared with a full backup, an incremental backup is usually...

A smaller and faster to run

B larger and slower to run

3. On Monday you take a full backup. On Tuesday you take an incremental backup. What does the Tuesday backup contain?

A Only the files changed since Monday's full backup

B Every file on the system

4. On Wednesday you take another incremental backup. Which files does it copy?

A Files changed since Monday's full backup

B Files changed since Tuesday's incremental backup

5. To restore data from incremental backups, you need...

A only the most recent incremental backup

B the full backup plus every incremental backup since it

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1incremental backup		ACopies only the files changed since the last backup of any type (full or incremental)
2Full + Inc1 + Inc2 + Inc3		BMon: Full 50 GB \| Tue: Inc 1 GB \| Wed: Inc 2 GB
3Small and fast: each incremental backup only copies files changed since the last backup of any type		CRestoring needs the full backup plus every increment since it (Tue, Wed, Thu). Skipping increments means changes are missing.
4Restore needs the full backup plus every increment, applied in order		DThis describes a differential backup. An incremental backup only copies changes since the last backup of any type, which here is Tuesday's incremental.
5Wed Inc copies everything changed since Monday's Full backup		EThe set of backups needed to restore data after the third incremental backup
6Restore Thursday using the Full backup + Wed Inc only		Frestore(Full, Inc1, Inc2, Inc3)

Definitions

incremental backup

Fill in the Blanks

Complete each line of code by filling in the missing parts.

backupType ← ___________

incrementalSize ← _____

restore ← __________ + allIncrements

Mon: full backup Tue: incremental, changes since Mon Wed: incremental, changes since ___

FOR inc IN incrementsInOrder _____(inc)

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A Sun: full backup

B Mon: copy every file again

C Tue: changes since Mon

Question 2

A Sun: full backup

B Mon: changes since Sun

C Tue: changes since Mon

D Wed: changes since Sun

Question 3

A Disk fails on Thursday

B Restore the full backup first

C Then restore only the last one

Question 4

A Incremental: large and slow

B Copies files changed since the

C last backup of any type

Question 5

A IF changed since last full

B copy file to backup

C ELSE skip the file

Answer Key

Incremental backup

Section A: Quick Questions

A — the last backup of any type (full or incremental)

A — smaller and faster to run

A — Only the files changed since Monday's full backup

B — Files changed since Tuesday's incremental backup

B — the full backup plus every incremental backup since it

Section B: Match the Pairs

incremental backup → Copies only the files changed since the last backup of any type (full or incremental)

Full + Inc1 + Inc2 + Inc3 → The set of backups needed to restore data after the third incremental backup

Small and fast: each incremental backup only copies files changed since the last backup of any type → Mon: Full 50 GB | Tue: Inc 1 GB | Wed: Inc 2 GB

Restore needs the full backup plus every increment, applied in order → restore(Full, Inc1, Inc2, Inc3)

Wed Inc copies everything changed since Monday's Full backup → This describes a differential backup. An incremental backup only copies changes since the last backup of any type, which here is Tuesday's incremental.

Restore Thursday using the Full backup + Wed Inc only → Restoring needs the full backup plus every increment since it (Tue, Wed, Thu). Skipping increments means changes are missing.

Section C: Definitions

incremental backup — A backup that copies only files changed since the last backup of any type. It is small and fast, but a restore needs the full backup plus every increment.

Section D: Fill in the Blanks

backupType ← incremental

incrementalSize ← small

restore ← fullBackup + allIncrements

Mon: full backup
Tue: incremental, changes since Mon
Wed: incremental, changes since Tue

FOR inc IN incrementsInOrder
    apply(inc)

Section E: Spot the Error

B — An incremental backup copies only the files that changed since the last backup. Copying every file again would be a full backup. It should be 'Mon: changes since Sun'.

D — An incremental backup compares files with the last backup of any type, which was Tuesday's. Comparing with Sunday's full backup describes a differential backup. It should be 'Wed: changes since Tue'.

C — Each increment holds only a slice of the changes, so a restore needs the full backup plus every increment in order. It should be 'Then restore every increment'.

A — Because an incremental backup copies only recently changed files, it is small and fast, not large and slow.

A — An incremental backup checks for changes since the last backup of any type, not just the last full backup. The condition should be 'IF changed since last backup'.