Full, Incremental, Differential, and Synthetic Full Backups for A+
Short answer
- Full backup: simplest to restore (single media set) but slower and uses most storage and I/O during the backup window. - Incremental: fast backups and lower storage per incremental, but restore requires the last full plus every incremental in the chain; longer restore time and higher restore fragility. - Differential: compromises between full and incremental; backup time increases until the next full, but restore needs only the last full plus the most recent differential.
Why it appears on the exam
- Recognition: define each backup type by a short cue. Eg: "Which backup captures only changes since the last full backup?" Answer: differential. - Scenario matching: given restore-time constraints, choose differential vs incremental vs full. - Best-choice selection: select synthetic full when production I/O must be minimized but a full backup image is still required.
Key concepts
Concept 1
Required terms
full backup: A backup that captures the entire target dataset in a single backup operation. incremental backup: A backup that saves only the data changed since the last backup of any type (often since the last backup event). differential backup: A backup that saves data changed since the last full backup. synthetic full: A full backup image reconstructed from existing full and incremental/differential data without re-reading all source data at backup time.
Example
Small office daily plan: weekly full on Sunday, incremental on weekdays. This saves nightly window time but requires chaining to restore.
Concept 2
How Full, Incremental, Differential, and Synthetic Full Backups works
- Full backup: simplest to restore (single media set) but slower and uses most storage and I/O during the backup window. - Incremental: fast backups and lower storage per incremental, but restore requires the last full plus every incremental in the chain; longer restore time and higher restore fragility. - Differential: compromises between full and incremental; backup time increases until the next full, but restore needs only the last full plus the most recent differential.
Example
Rapid-restore daily differential with weekly full gives quicker restores (only last differential plus the weekly full) at the cost of increasing nightly backup size.
Concept 3
Common confusion
- "Incremental" vs "differential": both capture changes but use different reference points. If asked which needs only two files to restore, choose differential (last full + differential). - Synthetic full is not identical to performing a new full read; it is assembled on the backup side. - Equating backup type with compression or encryption; these are separate attributes of backup storage.
Example
Low-impact alternative: system performs incremental backups and then a synthetic full on the backup server weekly to present a full backup without running a heavy full job on the production server.
Concept 4
Core 2 (220-1202) question cues
Recognition: define each backup type by a short cue. Eg: "Which backup captures only changes since the last full backup?" Answer: differential; Scenario matching: given restore-time constraints, choose differential vs incremental vs full; Best-choice selection: select synthetic full when production I/O must be minimized but a full backup image is still required.
Example
Small office daily plan: weekly full on Sunday, incremental on weekdays. This saves nightly window time but requires chaining to restore.
Sample questions
Select an answer to reveal the explanation. For tracked practice and weak-area review, use the Cultiv8 app.
Q1.An A+ support scenario describes this situation: Low-impact alternative: system performs incremental backups and then a synthetic full on the backup server weekly to present a full backup without running a heavy full job on the production server. Which answer fits best?
Q2.A technician sees this situation: Rapid-restore daily differential with weekly full gives quicker restores (only last differential plus the weekly full) at the cost of increasing nightly backup size. Which answer should they choose?
Q3.Read this A+ scenario: Low-impact alternative: system performs incremental backups and then a synthetic full on the backup server weekly to present a full backup without running a heavy full job on the production server. Which term or action matches it?
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