A node is assigned a role during its creation and can take any one of these roles:
Active: Stores data and allows client access. Active nodes are in mirrored pairs.
Spare: Allows client access, but does not store data. After initializing data devices, monitors other data nodes to initiate repair if another node becomes unavailable.
Offline: Provide no services until their role changes. When placed back online, its role can change back to its former role.
Shutdown: An intermediate step between active and offline, waiting for a spare node to take over its functioning. After the spare node has taken over, the node is taken offline.