• Relational Database Service

  1. Help Center
  2. Relational Database Service
  3. User Guide
  4. Introduction
  5. Basic Concepts

Basic Concepts

Automated Backups

When you create a DB instance, the automated backup policy is enabled by default. After the DB instance is created, you can modify the policy. RDS will automatically create full backups for DB instances based on your settings.

Manual Backups

Manual backups are user-initiated full backups of DB instances. They are retained until you delete them manually.

Regions and AZs

A region is a geographic area in which resources used by your RDS are located. Each region comprises one or more AZs and is completely isolated from other regions. AZs in the same region can communicate with one another through an internal network, while those in different regions cannot communicate with one another through an internal network.

Public cloud data centers are deployed in locations around the world, including North America, Europe, and Asia. Through provisioning RDS to specific regions, applications can be designed to better meet specific regional requirements, such as complying with local laws.

An availability zone (AZ) is a region in which power and networks are physically isolated. AZs in the same region can communicate with each other over an intranet. Each AZ provides cost-effective and low-latency network connections that are unaffected by faults that may occur in other AZs. Therefore, provisioning RDS in separate AZs protects your applications against local faults that occur in a single location.


Projects are used to group and isolate OpenStack resources (compute, storage, and network resources). A project can be a department or a project team. Multiple projects can be created for one account.