This topic describes the three instance families of ApsaraDB for RDS. They are general-purpose, general-purpose 2, and dedicated instance families.
|Instance family||Description||Application scenario|
|General-purpose 2 instance
Note The general-purpose 2 instance family is only supported for the High-availability Edition used with SQL Server.
||Users are less concerned with performance and stability.|
|Dedicated instance||A dedicated instance occupies exclusive CPU and memory resources allocated to it.
Its performance and stability are independent of the other instances on the same physical
The top configuration of this instance family is dedicated host. A dedicated-host instance occupies all resources on the physical host housing it.
|Users are engaged in database-centered businesses such as finance, e-commerce, governmental affairs, and other large- and medium-sized Internet services.|
The following figure shows differences between the general-purpose, general-purpose 2, and dedicated instance families.
The three instance families each have their own different performance metrics and therefore cannot be directly compared. The following table is a comparison in cost-effectiveness between them by using instance types with similar specifications as an example. This comparison provides a basis for you to make your purchase decisions.
|Instance family||CPU and memory||Storage capacity||Maximum connections||Maximum IOPS||Monthly subscription price|
|General-purpose instance or general-purpose 2 instance||4 cores, 16 GB||500 GB||4,000||7,000||USD 2,100|
|Dedicated instance||4 cores, 32 GB||500 GB||5,000||9,000||USD 3,650|
Based on the above comparison, a dedicated instance costs 70% more but provides twice as much memory capacity, 25% more connections, and 28% higher IOPS than a general-purpose instance or general-purpose 2 instance. This means that the dedicated instance family delivers the highest cost-effectiveness among the three instance families.
Instance typesFor more information about instance types and their specifications such as the number of CPU cores, memory capacity, storage capacity, maximum number of connections, and IOPS, see Instance types.
For more information about the price of each instance type, visit ApsaraDB RDS for MySQL.
Change instance types
You can change the instance family and specifications of your ApsaraDB for RDS instance as needed.
For more information, see the following topics:
Why does an entry-level instance outperform an enterprise-level instance?
An entry-level instance belongs to the general-purpose or general-purpose 2 instance family, whereas an enterprise-level instance belongs to the dedicated instance family. Therefore, an entry-level instance supports a larger maximum number of connections and delivers higher IOPS than an enterprise-level instance with the same CPU and memory specifications. However, an enterprise-level instance is more stable due to its exclusive CPU and memory resources. For more information, see Overview.