Scaleway Database Instances API
A Database Instance is made up of one or multiple dedicated compute nodes running a single database engine. Two node settings are available: **High-Availability (HA)**, with a main node and one replica, and **standalone** with a main node. The HA standby node is linked to the main node, using synchronous replication. Synchronous replication offers the ability to confirm that all changes intended by a transaction have been transferred and applied to the synchronous replica node, providing durability to the data. **Note**: HA standby nodes are not accessible to users unless the main node becomes unavailable and the standby takes over. If you wish to run queries on a read-only node, you can use [Read Replicas](#path-read-replicas-create-a-read-replica) Read Replicas can be used for certain read-only workflows such as Business Intelligence, or for a read-only scaling of your application. Read Replicas use asynchronous replication to replicate data from the main node.