ApsaraDB for MyBase provides the following two types of storage media: local SSD and enhanced SSD (ESSD).

Overview

  • ESSDs
    We recommend that you use ESSDs. ESSDs are a new type of high-performance disks that are developed by Alibaba Cloud based on the next-generation distributed block storage architecture. ESSDs use 25 Gigabit Ethernet and remote direct memory access (RDMA) technologies to deliver up to one million random IOPS and reduce one-way latency. ESSDs are divided into the following three types based on the performance level (PL):
    • ESSD: An ESSD of PL1 is a standard ESSD.
    • PL2 ESSD: An ESSD of PL2 can deliver approximately twice the IOPS and throughput that are delivered by an ESSD of PL1.
    • PL3 ESSD: An ESSD of PL3 can deliver up to 20 times the IOPS that is delivered by an ESSD of PL1. An ESSD of PL3 can also deliver approximately 11 times the throughput that is delivered by an ESSD of PL1. ESSDs of PL3 are suitable for scenarios in which highly concurrent I/O requests must be processed at low read and write latency.
  • Local SSDs

    Local SSDs are SSDs that are deployed on the same node as the database engine. You can use local SSDs to reduce I/O latency. The following table describes the performance of local SSDs.

    Metric rds.i2.xlarge and rds.i2g.2xlarge Other i2 and i2g instance types Instances of the highest specifications
    Maximum capacity 894 GiB 1,788 GiB 8 × 1,788 GiB
    Maximum read IOPS 150,000 300,000 1,500,000
    Maximum read throughput 1 GB/s 2 GB/s 16 GB/s
    Maximum write throughput 0.5 GB/s 1 GB/s 8 GB/s
    Access latency Within microseconds

    The values in the Instances of the highest specifications column represent the performance of rds.i2.16xlarge instances. These values represent the performance of local SSDs of the highest specifications in the i2 instance family.

Comparison between storage types

Table 1. Performance comparison
Storage type I/O performance Specification flexibility Scalability
Local SSD

★★★★★

Provides low I/O latency and high I/O performance.

★★★★★

The storage capacity of an instance is not related to the instance type. You can adjust the storage capacity of an instance based on your business requirements.

★★★

Requires hours to copy data when you scale the database system.

ESSD

★★★★★

Provides higher I/O performance than standard SSDs.

★★★★★

Allows you to scale the database system in minutes.

Storage types supported by database engines

Database engine Host storage type
MySQL
  • If you create an ApsaraDB for MyBase dedicated cluster that runs MySQL database engine and you set the Deployment Method parameter to Highly usable, hosts in this dedicated cluster can use local SSDs and ESSDs.
  • If you create an ApsaraDB for MyBase dedicated cluster that runs MySQL database engine and you set the Deployment Method parameter to Enterprise, hosts in this dedicated cluster can use ESSDs.
SQL Server
  • ESSDs
  • PL2 ESSDs
  • PL3 ESSDs
PostgreSQL

ESSDs