Before you purchase an ApsaraDB RDS instance, we recommend that you understand the benefits of various configurations. This way, you can select a suitable configuration to meet your business requirements.

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Introduction to RDS editions, storage types, instance families, and storage engines

Before you create an RDS instance, you determine which configuration is the most cost-effective and stable for your business based on factors such as performance, prices, and loads. The RDS edition, storage type, and instance family that you select affect one another. For more information, see Create an ApsaraDB RDS for MySQL instance.

Note If you want to create an RDS instance that runs MySQL 8.0, you must select a default storage engine.
  • RDS editions

    ApsaraDB RDS provides the following four editions: Basic Edition, High-availability Edition, Cluster Edition, and Enterprise Edition.

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

    For more information, see RDS 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 RDS instance and one secondary RDS instance. These instances work in the high-availability architecture. This edition is suitable for more than 80% of the actual business scenarios.

    For more information, see High-availability Edition.

    • 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 RDS instance, one secondary RDS instance, and up to seven read-only RDS instances. The primary and secondary RDS instances work in the high availability architecture. The read-only RDS instances 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, if you select the Cluster Edition, your database system consists of only one primary RDS instance and one secondary RDS instance. You can create read-only RDS instances later based on your business requirements.

    For more information, see Cluster 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 RDS instance and two secondary RDS instances. Data is synchronously replicated from the primary RDS instance to the secondary RDS instances. This allows you to ensure data consistency and finance-grade 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
    PolarDB for MySQL PolarDB for MySQL delivers faster scaling, larger storage capacity, and lower replication latency.

    For more information, see What is PolarDB?.

    • Production databases for large- and medium-sized enterprises
    • Databases in industries such as the Internet, IoT, online retail, logistics, and gaming
    • Important databases in the finance, securities, and insurance industries that require high data security
  • Storage types

    ApsaraDB RDS provides three storage types: local SSDs, standard SSDs, and enhanced SSDs (ESSDs). All storage types meet the reliability, persistence, and read/write performance requirements that are specified in Alibaba Cloud service level agreement (SLA).

    • Local SSDs

      Local SSDs are a recommended type of storage medium. Local SSDs reside on the same physical host as the database engine that is used. You can store data on local SSDs to reduce I/O latencies.

    • Standard SSDs
      Standard SSDs are elastic block storage devices that are designed based on a distributed storage architecture. You can store data on standard SSDs to separate computing from storage.
      Note Standard SSDs are being phased out. We recommend that you use ESSDs.
    • ESSDs
      ESSDs are also a recommended type of storage medium. ESSDs are developed by Alibaba Cloud based on the next-generation distributed block storage architecture. ESSDs deliver ultra high storage performance. ESSDs are integrated with 25 Gigabit Ethernet and remote direct memory access (RDMA) technologies. ESSDs can help you reduce one-way latencies and process up to 1 million read and write requests at random per second. ESSDs are provided in three performance levels (PLs) as indicated on the ApsaraDB RDS buy page:
      • ESSD PL1: This is the most basic PL of ESSDs.
      • ESSD PL2: An ESSD of PL2 delivers IOPS and throughput that are approximately two times the IOPS and throughput delivered by an ESSD of PL1.
      • ESSD PL3: An ESSD of PL3 delivers IOPS that is up to 20 times the IOPS delivered by an ESSD of PL1. An ESSD of PL3 also delivers throughput that is up to 11 times the throughput delivered by an ESSD of PL1. ESSDs of PL3 are suitable for business scenarios in which highly concurrent requests must be processed with high I/O performance and at low read and write latencies.
  • Instance families

    ApsaraDB RDS provides various instance families based on the number of cores, memory capacity, number of connections, and IOPS. Each instance family includes multiple instance types.

    Instance family Description Scenarios
    Shared instance family
    • A shared RDS instance exclusively occupies the allocated memory and storage resources, but shares CPU resources with the other shared RDS instances that are deployed on the same physical host.
    • CPU resources are highly reused among the shared RDS instances that are deployed on the same physical host. The reuse of CPU resources helps maximize cost-effectiveness.
    • Shared RDS instances that are deployed on the same physical host may compete for resources.
    • You pursue high cost-effectiveness to reduce costs.
    • You require high availability rather than high performance stability from your ApsaraDB RDS for SQL Server instance.
    General-purpose instance family
    • A general-purpose RDS instance exclusively occupies the allocated memory resources, but shares CPU and storage resources with the other general-purpose RDS instances that are deployed on the same physical host.
    • CPU resources are moderately reused among the general-purpose RDS instances that are deployed on the same physical host. The reuse of CPU resources helps increase cost-effectiveness.
    • The storage capacity of a general-purpose RDS instance is independent of the number of cores and the memory capacity. You can specify the storage capacity based on your business requirements.
    You do not require high performance stability.
    Dedicated instance family
    • A dedicated RDS instance exclusively occupies the allocated CPU and memory resources. The performance of a dedicated RDS instance remains stable and is not affected by the other instances that are deployed on the same physical host.
    • Dedicated host instance types are the highest instance types in the dedicated instance family. A dedicated host RDS instance occupies all resources on the physical host on which the RDS instance is deployed.
    You use databases as core systems in sectors such as finance, e-commerce, public affairs, and large-sized or medium-sized Internet services.
  • Storage engines

    If you want to create an RDS instance that runs MySQL 8.0, you can select one of the following storage engines:

    • InnoDB: the default storage engine provided by open source MySQL. The InnoDB storage engine that is used for ApsaraDB RDS is optimized by Alibaba Cloud.
    • X-Engine: the storage engine developed by Alibaba Cloud. X-Engine is compatible with InnoDB. X-Engine outperforms InnoDB in terms of disk space usage and cost-effectiveness. X-Engine is more suitable for scenarios such as data archiving than InnoDB. For more information, see Introduction to X-Engine.

Select configuration for an RDS instance

Perform the following steps to select a suitable configuration for an RDS instance:

  1. Select an RDS edition.

    We recommend that you select RDS High-availability Edition. If you select RDS High-availability Edition, your database system consists of a primary RDS instance and a secondary RDS instance to ensure high availability. RDS High-availability Edition is suitable for medium-sized enterprises and large-sized enterprises and for industries such as Internet, Internet of Things (IoT), online retail, logistics, and gaming.

    For data security purposes, we recommend that you select RDS Enterprise Edition or RDS Cluster Edition. These editions are suitable for crucial databases in large-sized enterprises and for financial, securities, and insurance industries. RDS Enterprise Edition is available only when you select the MySQL engine. RDS Cluster Edition is available only when you select the SQL Server engine.

    Select an RDS edition.
  2. Select a storage type.

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

    The maximum IOPS of a standard SSD or ESSD varies based on the instance type and the storage capacity. The following table lists the formulas that you can use to calculate the maximum IOPS of an RDS instance that uses standard SSDs or ESSDs.

    Storage type ESSD Standard SSD
    PL PL3 PL2 PL1 None

    Formula

    (The storage capacity is measured in the unit of GB.)

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

    The specifications of an RDS instance type include the number of cores, memory capacity, maximum number of connections, and maximum IOPS. When you create an RDS instance, you can select one of the following instance type levels: entry level or enterprise level. Then, you can select an instance type based on your business requirements. The entry level provides the shared instance family and the general-purpose instance family. The enterprise level provides the dedicated instance family.

    Select an instance type
    Note If you select the standard SSD or ESSD storage type, the IOPS becomes N/A in the ApsaraDB RDS console. This is because ApsaraDB RDS calculates the IOPS based on the selected storage type. For more information, see Select a storage type in this section.
  4. Select a storage engine.

    If you want to create an RDS instance that runs MySQL, we recommend that you select X-Engine. X-Engine costs approximately 50% less than InnoDB but delivers comparable performance. For more information, see Usage notes.

Check and modify the configuration of an RDS instance

After you create and start to use an RDS instance, we recommend that you continue to monitor the performance of the RDS instance for a specific period of time. This way, you can check whether the configuration of the RDS instance is suitable.

For example, if the memory usage is high, we recommend that you log on to the RDS instance to troubleshoot the issue. If no exceptions occur, you can modify the configuration of the RDS instance. If exceptions occur, you can modify the allocation of memory on the RDS instance. For more information, see the following topics:

Create an RDS instance

References