Why replication provides redundancy in Redis - Challenge Your Understanding

Challenge - 5 Problems

🧠 Conceptual

intermediate

Why does replication improve data availability?

In Redis, replication means copying data from one server (master) to another (slave). Why does this help keep data safe and available?

A Because if the master fails, the slave has a copy to continue serving data.

B Because replication compresses data to save space.

C Because replication deletes old data to keep the database small.

D Because replication encrypts data to prevent hacking.

💡 Hint

Think about what happens if the main server stops working.

Replication creates copies of data on other servers. If the main server fails, these copies can take over, so data is not lost and remains accessible.

🧠 Conceptual

intermediate

How does replication reduce downtime?

Which statement best explains how replication helps reduce downtime in Redis?

A Replication automatically deletes data to speed up recovery.

B Replication allows read requests to be served by slaves, reducing load on the master.

C Replication prevents network failures by using special cables.

D Replication encrypts data to avoid downtime.

💡 Hint

Think about how spreading work helps keep the system fast and available.

Slaves can handle read requests, so the master is less busy and can focus on writes. If the master fails, slaves can take over quickly, reducing downtime.

❓ query_result

advanced

What is the output of this Redis command sequence with replication?

Assume a Redis master has a key count set to 10. It replicates to a slave. Then the master increments count by 5. What value will the slave return for count after replication?

Redis

MASTER: SET count 10
SLAVE: GET count
MASTER: INCRBY count 5
SLAVE: GET count

A 10 then 15

B 15 then 15

C 10 then 10

D Error on slave GET

💡 Hint

Remember slaves update their data after the master changes.

The slave initially has 10 for count. After the master increments it to 15, the slave updates to 15 too.

🔧 Debug

advanced

Why does this Redis slave not have updated data?

A Redis slave is not showing the latest data after the master updates a key. Which reason explains this behavior?

A The slave has a different key name.

B The master deleted the key before replication.

C The slave is disconnected and not receiving replication updates.

D The master is running in read-only mode.

💡 Hint

Check the connection status between master and slave.

If the slave is disconnected, it cannot get updates from the master, so its data is stale.

🧠 Conceptual

expert

Why is replication considered a redundancy strategy in Redis?

Choose the best explanation why replication is a form of redundancy in Redis systems.

A Because it compresses data to reduce storage needs.

B Because it deletes old data to keep the database clean.

C Because it encrypts data to secure it from unauthorized access.

D Because it creates multiple copies of data on different servers to prevent data loss.

💡 Hint

Think about what redundancy means in data storage.

Redundancy means having extra copies of data so if one copy is lost or damaged, others remain available. Replication achieves this by copying data to multiple servers.