Does rook-ceph automatically expand to add more storage when adding additional nodes to a cluster?

Rook will automatically provision storage space on new nodes that are added to a cluster, but you won’t see more storage available to the cluster as a whole until you add a fourth node.

Rook is configured for triple replication, so it will store the same data in three places. Any nodes past the third will increase the total amount of storage available in the cluster. If you have three nodes, each with 100 GB of storage available for Rook, you will be able to use Rook storage totaling 100 gigabytes. If you add a fourth node with the same amount of space, you will now be able to use 133 GB of Rook storage.