Enhanced SSDs (ESSDs) integrate 25 Gigabit Ethernet and remote direct memory access (RDMA) technologies to reduce latency and deliver up to 1 million random input/output operations per second (IOPS). This topic provides general information about Alibaba Cloud ESSDs, such as performance levels (PLs), usage scenarios, and performance specifications.

Specifications

The API parameter value cloud_essd indicates ESSDs. ESSDs are divided into four PLs based on the maximum performance per disk.

ESSD attribute PL
PL3 PL2 PL1 PL0
Performance description Ultra-high maximum concurrent I/O performance and ultra-low I/O latency High maximum concurrent I/O performance and low I/O latency Moderate maximum concurrent I/O performance and low I/O latency Moderate maximum concurrent I/O performance and low I/O latency
Capacity range (GiB) 1,261~32,768 461~32,768 20~32,768 40~32,768
Data durability 99.9999999% 99.9999999% 99.9999999% 99.9999999%
Maximum IOPS per disk 1,000,000 100,000 50,000 10,000
Maximum throughput per disk (MB/s) 4,000 750 350 180
Formula for calculating the IOPS per disk min{1,800 + 50 × Capacity, 1,000,000} min{1,800 + 50 × Capacity, 100,000} min{1,800 + 50 × Capacity, 50,000} min{1,800 + 12 × Capacity, 10,000}
Formula for calculating the throughput per disk (MB/s) min{120 + 0.5 × Capacity, 4,000} min{120 + 0.5 × Capacity, 750} min{120 + 0.5 × Capacity, 350} min{100 + 0.25 × Capacity, 180}
Example scenario Large and medium-sized relational databases for core business and NoSQL databases, and large SAP and Oracle databases Medium-sized relational databases and NoSQL databases, medium-sized Elasticsearch distributed logs: Elasticsearch, Logstash, and Kibana (ELK) log clusters, and enterprise-level commercial software such as SAP and Oracle Small and medium-sized MySQL and SQL Server databases, small and medium-sized ELK log clusters, enterprise-level commercial software such as SAP and Oracle, and container applications Small and medium-sized MySQL and SQL Server databases, small and medium-sized ELK log clusters, enterprise-level commercial software such as SAP and Oracle, and container applications
Recommended system or data disks to be replaced with ESSDs in recommended business scenarios Data disks of instance families that are equipped with local SSDs and have 16 or more vCPUs (i1, i2, and i2g) Standard SSDs and data disks of instance families that are equipped with local SSDs (i1, i2, and i2g) Standard SSDs System disks
Note For information about how to perform stress testing on ESSDs, see Test the IOPS performance of an enhanced SSD.

Billing methods

ESSDs support the pay-as-you-go and subscription billing methods. For more information, see Create a disk.

For information about the pricing of ESSDs at different PLs, see the Pricing tab on the Elastic Compute Service page.

Scenarios

ESSDs are suitable for the following latency-sensitive applications or I/O intensive business scenarios:

  • Large online transaction processing (OLTP) databases: relational databases such as MySQL, PostgreSQL, Oracle, and SQL Server
  • NoSQL databases: non-relational databases such as MongoDB, HBase, and Cassandra databases
  • Elasticsearch distributed logs: ELK log analysis

Capacity and PLs

The performance of a storage device is closely related to the capacity of the device. A storage device that has a larger capacity provides higher data processing capabilities. All ESSDs have the same I/O performance per unit of capacity. However, the performance of ESSDs linearly increases together with its capacity until the maximum performance per disk at the PL is reached.
PL ESSD capacity range (GiB) Maximum IOPS Maximum throughput (MB/s)
PL0 40~32,768 10,000 180
PL1 20~32,768 50,000 350
PL2 461~32,768 100,000 750
PL3 1,261~32,768 1,000,000 4,000
  • Example 1: If Alex selects 20 GiB of storage capacity when Alex creates an ESSD in the ECS console, PL1 is the only available option. The PL1 ESSD delivers a maximum of 50,000 IOPS. Create an ESSD in the ECS console
  • Example 2: If Alex selects 32,000 GiB of storage capacity when Alex creates an ESSD in the ECS console, all PLs are available. A maximum of 10,000 IOPS is delivered for PL0, 50,000 IOPS for PL1, 100,000 IOPS for PL2, and 1,000,000 IOPS for PL3. Create an ESSD in the ECS console

Storage I/O performance of instance types

The storage I/O performance of some new-generation instance families is proportional to the specifications of instance types. For example, in the g6se storage enhanced instance family, the higher the specifications an instance type has, the higher storage IOPS and throughput it can deliver. For more information, see Storage I/O performance.

The following section describes the relationship between instance types and ESSDs in terms of performance:
  • If the total performance of ESSDs of an instance does not exceed the storage I/O performance of the instance type, the total performance of the ESSDs prevails.
  • If the total performance of ESSDs of an instance exceeds the storage I/O performance of the instance type, the storage I/O performance of the instance type prevails.

The actual storage performance differs when instances of different instance types are attached with ESSDs at different PLs. In the following examples, g6se is used:

  • Example 1: Alex creates a 16 GiB instance of the ecs.g6se.xlarge instance type. The maximum IOPS that this instance type can deliver is 60,000. Then, Alex attaches a PL2 ESSD to the instance. The ESSD has a capacity of 2,000 GiB and a maximum of 100,000 IOPS. The maximum IOPS of the instance is limited by the maximum IOPS of the instance type to 60,000.
  • Example 2: Alex creates a 64 GiB instance of the ecs.g6se.4xlarge instance type. The maximum IOPS that this instance type can deliver is 150,000. Then, Alex attaches three PL2 ESSDs to the instance. Each ESSD has a capacity of 2,000 GiB and a maximum of 100,000 IOPS. The total maximum IOPS that these ESSDs can deliver is 300,000. The maximum IOPS of the instance is limited by the maximum IOPS of the instance type to 150,000.
  • Example 3: Alex creates a 64 GiB instance of the ecs.g6se.4xlarge instance type. The maximum IOPS that this instance type can deliver is 150,000. Then, Alex attaches a PL3 ESSD to the instance. The ESSD has a capacity of 2,000 GiB and a maximum of 101,800 IOPS. The maximum IOPS of the instance is not limited by the maximum IOPS of the instance type, but is limited by the maximum IOPS of the ESSD to 101,800.

Instance families supported by ESSDs

For information about instance families supported by ESSDs at PL0, PL1, PL2, and PL3, see Instance families.