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RDS for SQL Server

Overview

Common concepts

Common concepts

This topic summarizes the glossary of cloud database instances of RDS for SQL Server.

Term	Concept
Region	The geographical location where the data is located.
Availability Zones	AZ for short. Each region has multiple isolated zones, called availability zones.
Main Instance	RDS for SQL Server is the basic unit for cloud resource management. The specifications of the instance (e.g. CPU cores, memory size, etc.) vary, and the performance of the instance also varies. For more information on instance specifications, see Product Specifications.
Read-only instance	A read-only instance is a copy of the primary instance and is primarily used to handle read requests, but not write requests. Read-only instances maintain data consistency with the primary instance by periodically replicating data from the primary instance. A read-only instance can perform read operations independently of the primary instance without affecting the performance of the primary instance.
Instance Type	Different choices of SQL Server instances in terms of node specifications, capabilities, and types.
Primary Node	The primary data node is the base node for SQL Server instances to provide services externally.
Secondary Node	Secondary data node, when the primary node fails, it can switch to a secondary node that provides services to the primary node and externally.
Private Network (VPC)	Virtual Private Cloud (VPC) is an isolated network environment with higher security and performance than traditional classical networks.
High Availability	Abbreviated as HA. The business stability is guaranteed through the primary and secondary architecture. After the primary node fails, it will automatically detect and complete the second-level primary and secondary switching.
Private Internet Address (Internal Address)	The connection address when accessing a SQL Server instance over a private network, such as when ECS and SQL Server instances are in the same VPC.

Last updated: 2025.10.11 16:39:14