• Database instance: a virtualized database server that consists of high-speed buffer pools and backend processes.
  • On-premises database: a database instance that is deployed in a non-cloud environment, such as a data center.
  • ECS-hosted self-managed database: a self-managed database instance that is deployed on an Elastic Compute Service (ECS) instance.
  • Cluster: a collection of one or more database instances of the same database engines, such as MySQL, Oracle, or SQL Server. A database instance belongs to only one cluster.
  • Database gateway: a daemon process that is deployed in the same environment as a database. A database gateway collects and computes performance data, but does not collect business data. A database gateway encrypts data before it transmits the data. For more information, see Database gateway overview.