The "all" Quorum instance. All replicas that must respond to a read or write request before it is considered successful.

The "default" Quorum instance. The default number of replicas must respond to a read or write request before it is considered successful. Riak will use the bucket (or global) default value if this Quorum is used. The true default value can be found in a bucket's properties, and varies for different parameters.

The "one" Quorum instance. Only one replica must respond to a read or write request before it is considered successful.

The "quorum" Quorum instance. A majority of replicas must respond to a read or write request before it is considered successful.