This topic describes the principles to select ApsaraDB for RDS instance types based on your business requirements.

Edition, storage type, instance family, and storage engine description

Before you create an ApsaraDB for RDS instance, you must select the most cost-effective and stable instance type based on performance, price, and workload. The following section describes the edition, storage type, and instance family of an RDS instance. For more information about instance parameters, see Create an ApsaraDB RDS for MySQL instance.

Note You must select a storage engine of an ApsaraDB RDS for MySQL 8.0 instance. The following section describes the selection method.
  • Edition

    ApsaraDB for RDS offers four editions: Basic Edition, High-availability Edition, Cluster Edition, and Enterprise Edition. The editions are described as follows.

    Edition Description Scenario
    Basic Edition Your database system consists of only one primary instance, and computing is separated from storage. This edition is cost-effective.

    For more information, see Basic Edition.

    • Personal learning
    • Small-sized websites
    • Development and test environments for small- and medium-sized enterprises
    High-availability Edition Your database system consists of one primary instance and one secondary instance. These instances work in the high-availability architecture. This edition is suitable for more than 80% of the actual business scenarios.
    • Production databases for large- and medium-sized enterprises
    • Databases in industries such as the Internet, Internet of Things (IoT), online retail, logistics, and gaming
    Cluster Edition Your database system consists of one primary instance, one secondary instance, and up to seven read-only instances that are used to increase the read capability. This edition is developed based on the AlwaysOn technology. It is supported only for SQL Server. By default, when you purchase the Cluster Edition, your database system consists of only a primary instance and a secondary instance. You must purchase read-only instances later based on your business requirements.

    For more information, see Cluster Edition (AlwaysOn Edition).

    Production databases for large- and medium-sized enterprises, such as online retailers, automobile companies, and ERP providers
    Enterprise Edition Your database system consists of one primary instance and two secondary instances. Data is synchronously replicated from the primary instance to the secondary instances. This allows you to ensure data consistency and finance-level reliability.

    For more information, see Enterprise Edition.

    • Important databases in the finance, securities, and insurance industries that require high data security
    • Important production databases for large-sized enterprises
  • Storage type

    ApsaraDB for RDS offers three storage types: local SSD, enhanced SSD (ESSD), and standard SSD. All of these storage types meet the reliability, persistence, and read/write performance requirements that are specified in Alibaba Cloud SLA. The storage types are described as follows.

    • Local SSDs

      This is a recommended storage type. A local SSD resides on the same server as the database engine. You can store data on a local SSD to reduce I/O latency.

    • Standard SSDs

      A standard SSD is an elastic block storage device that is designed based on a distributed storage architecture. You can store data on a standard SSD to separate computing from storage.

    • Enhanced SSDs (Recommended)
      This is also a recommended storage type. This new SSD product is designed by Alibaba Cloud based on next-generation distributed block storage architecture. It integrates 25 Gigabit Ethernet and remote direct memory access (RDMA) technologies to provide super high performance at low latency. An enhanced SSD can process up to 1 million random read/write requests per second. Enhanced SSDs come in three performance levels (PLs):
      • PL1: Enhanced SSDs of PL1 are regular enhanced SSDs.
      • PL2: An enhanced SSD of PL2 delivers input/output operations per second (IOPS) and throughput that are twice as high as those delivered by an enhanced SSD of PL1.
      • PL3: An enhanced SSD of PL3 delivers IOPS that is 20 times as high as the IOPS delivered by an enhanced SSD of PL1. It also delivers throughput that is 11 times as high as the throughput delivered by an enhanced SSD of PL1. Enhanced SSDs of PL3 are ideal for businesses that require high I/O performance in processing concurrent requests without increasing read/write latency.
      For more information about PLs, see block Block storage performance.
  • Instance family

    ApsaraDB for RDS offers a variety of instance families based on the CPU, memory, connections, and input/output operations per second (IOPS). Each instance family includes multiple instance types. The instance families are described as follows.

    Instance family Description Application scenario
    General-purpose 2 instance

    Not supported

    • A general-purpose 2 instance occupies exclusive memory resources allocated to it, but shares CPU and storage resources with the other general-purpose 2 instances on the same physical host.
    • CPU resources are frequently reused among general-purpose 2 instances on the same physical host to maximize CPU cost effectiveness.
    • General-purpose 2 instances may compete for resources.
    Note The general-purpose 2 instance family is only supported for the High-availability Edition used with SQL Server.
    • Users pursue cost-effectiveness.
    • Users prefer high availability to stability.
    General-purpose instance
    • A general-purpose instance occupies exclusive memory resources allocated to it, but shares CPU and storage resources with the other general-purpose instances on the same physical host.
    • CPU resources are commonly reused among general-purpose instances on the same physical host to increase CPU cost effectiveness.
    • The storage capacity of a general-purpose instance is independent of CPU cores and memory capacity. Storage capacity can be flexibly configured to fit into your business needs.
    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 host.

    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.
  • Storage engine

    ApsaraDB RDS for MySQL 8.0 supports the following storage engines:

    • InnoDB: the default storage engine of open source MySQL. ApsaraDB for RDS uses the InnoDB engine whose kernel is enhanced by Alibaba Cloud.
    • X-Engine: an engine developed by Alibaba Cloud and is compatible with InnoDB. X-Engine has better performance than InnoDB in disk space usage and low costs. X-Engine is designed for business scenarios such as data archiving. For more information, see X-Engine overview.

Select instance types

Perform the following steps to select an instance type.

  1. Select an edition

    We recommend that you select the High-availability Edition for scenarios related to the Internet, IoT, e-commerce retail, logistics, and gaming industries as well as large and medium-sized enterprises. This edition adopts the high-availability architecture that contains one primary instance and one secondary instance.

    We recommend that you select the Enterprise Edition (MySQL) or the Cluster Edition (SQL Server) for finance, securities, and insurance industries that require high data security as well as core databases of large enterprises.

    Select an edition
  2. Select a storage type

    We recommend that you select a local SSD or ESSD of a sufficient performance level based on the IOPS and throughput of your business. For more information about the differences between local SSDs and standard SSDs or ESSDs, see Features.

    The maximum IOPS of a standard SSD or ESSD is based on both instance type and storage capacity. To calculate the maximum IOPS of standard SSDs and ESSDs, use the formulas that are provided in the following table.

    Storage type ESSD Standard SSD
    Performance level PL3 PL2 PL1 N/A

    Formula for calculating maximum IOPS

    (Storage capacity measured in GB)

    min{1800 + 50 × Storage capacity, 1000000} min{1800 + 50 × Storage capacity, 100000} min{1800 + 50 × Storage capacity, 50000} min{1800 + 30 × Storage capacity, 25000}
    Select a storage type
  3. Select an instance type

    The specifications of an instance type include the number of CPU cores, memory capacity, maximum number of connections, and maximum IOPS. When you create an instance, you must select Entry-level (including shared and general-purpose instance families) or Enterprise-level (dedicated instance). Then, you can select an instance type based on your business requirements.

    Select an instance type
    Note When you select a standard SSD or ESSD for the storage type, the IOPS column displays N/A. You must calculate the IOPS based on the storage type.
  4. Select a storage engine

    If you want to use an ApsaraDB RDS for MySQL instance, we recommend that you select X-Engine as the storage engine. The storage cost of X-Engine is half of that of InnoDB, but the two storage engines deliver similar performance.

Check and adjust the instance type

After you select an instance type and start using the instance, we recommend that you check whether the instance type can meet the performance requirements based on the monitoring information.

For example, if you find the memory usage is high, we recommend that you log on to the instance to troubleshoot the issue. If no exceptions occur, you can switch to another instance type. If exceptions occur, you can adjust the memory allocation. For more information, see the following topics:

References