Storage I/O performance, also known as storage read/write performance, is the performance that is implemented when disks are attached to different ECS instance types. Metrics of storage I/O performance include IOPS and throughput.

I/O size

I/O (inputs/outputs or reads/writes) are random or sequential data requests initiated by an application. The volume of I/O requests is also known as the I/O size in KiB, such as 4 KiB, 256 KiB, and 1,024 KiB.

When designing the underlying storage architecture or selecting the instance type, you must consider metrics such as IOPS, I/O size, and throughput. IOPS × I/O size = Throughput. You can select different Block Storage devices and instance types based on the I/O request features of the application to achieve the best results:
  • If the application, such as offline analysis and data warehousing, requires a large amount of I/O, we recommend that you select the big data instance families with higher throughput.
  • If the application requires low-latency, random, and small-sized I/O, such as OLTP databases and enterprise-grade applications like SAP, we recommend that you select enhanced SSDs and standard SSDs with high IOPS.
For information about IOPS and throughput, see Block storage performance.

Storage I/O performance of instances

Note This section and subsequent sections are applicable only to the new generation of enterprise-grade instance families, including g6, c6, r6, g5se, hfg6, hfc6, and hfr6. They are not applicable to local disks.

The new generation of enterprise-grade instance families for Alibaba Cloud elastic compute features storage I/O performance isolation. Dedicated storage bandwidths are assigned to ECS instances and disks to avoid the storage I/O preemption among ECS instances. The new generation of enterprise-grade instance families ensures consistent storage I/O performance of applications even during peak hours.

For example, if your business application is one of the following applications that are I/O-sensitive and require stable storage I/O performance, we recommend that you select a new generation instance family that features storage I/O performance isolation:
  • Large and medium-sized database loads, such as Oracle, MySQL, SQL Server, PostgreSQL, Cassandra, and MongoDB databases.
  • Enterprise-grade applications, such as ERP and CRM.

Relationship between instance types and storage I/O performance

The storage I/O performance of an ECS instance varies with instance families and disk-attached instance types. The storage I/O performance of an instance depends on the instance type. A higher instance type provides higher storage I/O performance (IOPS and throughput).

After you create an ECS instance and attach disks to it, the final storage I/O performance of the ECS instance is determined as described in the following section:
  • Scenario 1: If the total storage performance of the attached disks exceeds the maximum storage I/O performance that the instance type can deliver, the final storage I/O performance of the instance is limited to the maximum storage I/O performance of that instance type.
  • Scenario 2: If the total storage performance of the attached disks does not exceed the maximum storage I/O performance that the instance type can deliver, the final storage I/O performance of the instance is limited to the maximum storage I/O performance of the disks.
Instances and their storage I/O performance

For example, the ecs.g6.8xlarge instance type features 60,000 IOPS. If a 1,600 GiB enhanced SSD PL2 is attached to an instance of the instance type and the IOPS of the enhanced SSD PL2 is 81,800, the maximum storage IOPS of the instance is 60,000 instead of 81,800. For information about the performance levels of enhanced SSDs, see Enhanced SSDs.

After you understand the relationship between instance storage performance and disk storage performance, you can choose instance types and Block Storage devices based on the performance data of instances and disks that meets your business needs. This prevents performance bottlenecks caused by using improper configurations.

Storage I/O performance of new generation of enterprise-grade instance families

The following table lists the storage I/O performance of the new generation of enterprise-grade instance families. For information about other metrics of the instance families, see Instance families.

Note In this table, the maximum IOPS is measured at 4 KiB I/O size and the maximum throughput is measured at 1,024 KiB I/O size. For information about the test method, see Performance tests on Block Storage.
Instance type Maximum IOPS (K, 4 KiB I/O) Maximum storage bandwidth (Gbit/s) Maximum throughput (MB/s, 1,024 KiB I/O)
ecs.g6.large 10 1.0 125
ecs.g6.xlarge 20 1.5 187.5
ecs.g6.2xlarge 25 2.0 250
ecs.g6.3xlarge 30 2.5 312.5
ecs.g6.4xlarge 40 3.0 375
ecs.g6.6xlarge 50 4.0 500
ecs.g6.8xlarge 60 5.0 625
ecs.g6.13xlarge 100 8.0 1,000
ecs.g6.26xlarge 200 16.0 2,000
ecs.c6.large 10 1.0 125
ecs.c6.xlarge 20 1.5 187.5
ecs.c6.2xlarge 25 2.0 250
ecs.c6.3xlarge 30 2.5 312.5
ecs.c6.4xlarge 40 3.0 375
ecs.c6.6xlarge 50 4.0 500
ecs.c6.8xlarge 60 5.0 625
ecs.c6.13xlarge 100 8.0 1,000
ecs.c6.26xlarge 200 16.0 2,000
ecs.r6.large 10 1.0 125
ecs.r6.xlarge 20 1.5 187.5
ecs.r6.2xlarge 25 2.0 250
ecs.r6.3xlarge 30 2.5 312.5
ecs.r6.4xlarge 40 3.0 375
ecs.r6.6xlarge 50 4.0 500
ecs.r6.8xlarge 60 5.0 625
ecs.r6.13xlarge 100 8.0 1,000
ecs.r6.26xlarge 200 16.0 2,000
ecs.g5se.large 30 1.0 125
ecs.g5se.xlarge 60 2.0 250
ecs.g5se.2xlarge 120 4.0 500
ecs.g5se.4xlarge 230 8.0 1,000
ecs.g5se.6xlarge 340 12.0 1,500
ecs.g5se.8xlarge 450 15.0 1,875
ecs.g5se.16xlarge 900 30.0 3,750
ecs.g5se.18xlarge 1,000 32.0 4,000
ecs.hfc6.large 10 1.0 125
ecs.hfc6.xlarge 20 1.5 187.5
ecs.hfc6.2xlarge 25 2.0 250
ecs.hfc6.3xlarge 30 2.5 312.5
ecs.hfc6.4xlarge 40 3.0 375
ecs.hfc6.6xlarge 50 4.0 500
ecs.hfc6.8xlarge 60 5.0 625
ecs.hfc6.10xlarge 100 8.0 1,000
ecs.hfc6.16xlarge 120 10.0 1,250
ecs.hfc6.20xlarge 200 16.0 2,000
ecs.hfg6.large 10 1.0 125
ecs.hfg6.xlarge 20 1.5 187.5
ecs.hfg6.2xlarge 25 2.0 250
ecs.hfg6.3xlarge 30 2.5 312.5
ecs.hfg6.4xlarge 40 3.0 375
ecs.hfg6.6xlarge 50 4.0 500
ecs.hfg6.8xlarge 60 5.0 625
ecs.hfg6.10xlarge 100 8.0 1,000
ecs.hfg6.16xlarge 120 10.0 1,250
ecs.hfg6.20xlarge 200 16.0 2,000
ecs.hfr6.large 10 1.0 125
ecs.hfr6.xlarge 20 1.5 187.5
ecs.hfr6.2xlarge 25 2.0 250
ecs.hfr6.3xlarge 30 2.5 312.5
ecs.hfr6.4xlarge 40 3.0 375
ecs.hfr6.6xlarge 50 4.0 500
ecs.hfr6.8xlarge 60 5.0 625
ecs.hfr6.10xlarge 100 8.0 1,000
ecs.hfr6.16xlarge 120 10.0 1,250
ecs.hfr6.20xlarge 200 16.0 2,000