RDB vs AOF comparison in Redis - Practice Questions

Challenge - 5 Problems

🧠 Conceptual

intermediate

Difference in Persistence Frequency

Which statement correctly describes how often Redis saves data to disk using RDB and AOF?

A RDB saves data at specified intervals, while AOF logs every write operation immediately or with minimal delay.

B RDB logs every write operation immediately, while AOF saves data only at specified intervals.

C Both RDB and AOF save data only when Redis is shut down.

D RDB and AOF both save data continuously in real-time without delay.

💡 Hint

Think about how each method balances performance and data safety.

RDB snapshots the dataset at intervals, which is efficient but may lose recent changes. AOF logs every write command, providing better durability.

🧠 Conceptual

intermediate

Recovery Speed Comparison

When Redis restarts, which persistence method generally allows faster recovery of data?

A Both RDB and AOF take the same time to recover data.

B AOF allows faster recovery because it replays a small log file.

C RDB allows faster recovery because it loads a single snapshot file.

D Neither RDB nor AOF can recover data after restart.

💡 Hint

Consider the size and format of files each method uses during recovery.

RDB loads a compact snapshot file, which is faster than replaying many commands from the AOF log.

❓ query_result

advanced

AOF File Growth Behavior

Given a Redis instance with frequent writes, what is the expected behavior of the AOF file size over time if no rewriting occurs?

A The AOF file size will randomly fluctuate without any pattern.

B The AOF file size will continuously grow larger as every write is appended.

C The AOF file size will shrink over time without any intervention.

D The AOF file size will remain constant because old commands are deleted automatically.

💡 Hint

Think about how AOF logs every write operation.

AOF appends every write command, so without rewriting, the file grows continuously.

🧠 Conceptual

advanced

Data Safety in Case of Crash

Which persistence method offers better data safety in case of a sudden Redis crash?

A AOF with fsync set to every write offers better data safety than RDB snapshots.

B RDB snapshots offer better data safety than AOF regardless of fsync settings.

C Both RDB and AOF offer the same data safety in case of a crash.

D Neither RDB nor AOF provide any data safety in case of a crash.

💡 Hint

Consider how often data is written to disk in each method.

AOF with frequent fsync ensures minimal data loss by writing every command to disk immediately, unlike RDB which saves snapshots less often.

❓ schema

expert

Choosing Persistence Strategy for High Write Load

You manage a Redis server with very high write load and need to minimize data loss but also want to keep server performance high. Which persistence strategy is best?

A Use only RDB snapshots at long intervals to reduce disk writes.

B Disable both AOF and RDB to maximize performance.

C Use AOF with fsync every write to maximize durability regardless of performance.

D Use AOF with fsync every second and enable RDB snapshots as a fallback.

💡 Hint

Balance durability and performance by combining methods.

Using AOF with fsync every second balances durability and performance, while RDB snapshots provide a fallback recovery point.