Adding and removing nodes in Redis - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does adding a node mean in a Redis cluster?

Adding a node means introducing a new Redis server to the cluster to share the data and workload, improving capacity and availability.

intermediate

How do you safely remove a node from a Redis cluster?

You first migrate the data from the node to be removed to other nodes, then use the cluster command to forget the node, ensuring no data loss.

beginner

What is the purpose of the 'CLUSTER MEET' command in Redis?

The 'CLUSTER MEET' command is used to add a new node to an existing Redis cluster by making nodes aware of each other.

intermediate

Why must slots be migrated when removing a node from a Redis cluster?

Slots hold the data keys. Migrating slots ensures data is moved safely to other nodes before removing the node, preventing data loss.

intermediate

What command helps to forget a node in a Redis cluster after removal?

The 'CLUSTER FORGET ' command removes the node from the cluster's configuration after its data has been migrated.

Which command is used to introduce a new node to a Redis cluster?

A CLUSTER MIGRATE

B CLUSTER FORGET

C CLUSTER MEET

D CLUSTER ADDNODE

CLUSTER MEET is the command that makes nodes aware of each other to form or expand a cluster.

Before removing a node, what must be done with its slots?

A Migrate them to other nodes

B Backup them locally

C Delete them immediately

D Ignore them

Slots must be migrated to other nodes to preserve data before removing a node.

What does the 'CLUSTER FORGET' command do?

A Removes a node from the cluster configuration

B Adds a node to the cluster

C Migrates slots between nodes

D Lists all nodes in the cluster

CLUSTER FORGET removes a node from the cluster's configuration after it is removed.

Why add nodes to a Redis cluster?

A To reduce data storage

B To increase capacity and availability

C To slow down queries

D To delete data

Adding nodes helps the cluster handle more data and stay available if some nodes fail.

What happens if you remove a node without migrating its slots?

A Nothing happens

B Cluster automatically backs up data

C Other nodes take over slots automatically

D Data on that node is lost

Removing a node without migrating slots causes data loss for keys in those slots.

Explain the steps to add a new node to a Redis cluster.

Think about how nodes become aware of each other and share data.

Describe how to safely remove a node from a Redis cluster without losing data.

Focus on data migration and cluster configuration update.