This topic provides general information about Alibaba Cloud enhanced SSD (ESSD) cloud disks, such as performance levels, scenarios, and performance specifications. ESSD cloud disks are based on a 25 GE network and remote direct memory access (RDMA) technology. They deliver a maximum random IOPS of 1 million per disk and low one-way latency.

Scenarios

ESSD cloud disks apply to the following scenarios where short latency and high throughput are required:

  • Online transaction processing (OLTP) databases (relational databases), for example, MySQL, PostgreSQL, Oracle, and SQL Server.
  • NoSQL databases (non-relational databases), for example, MongoDB, HBase, and Cassandra.
  • Real-time analysis applications, for example, Elasticsearch and ELK (Elasticsearch, Logstash, and Kibana) logging tools.

Specifications

The API value of ESSD cloud disks is cloud_essd. ESSD cloud disks are available in three performance levels (PLs). For more information, see How can I test the performance of an ESSD cloud disk?

The following table describes the specifications of ESSD cloud disks of different performance levels.

ESSD cloud disk attribute PL3 PL2 PL1
Capacity (GiB) 1,261-32,768 461-32,768 20-32,768
Data reliability 99.9999999% 99.9999999% 99.9999999%
Maximum IOPS of a single cloud disk 1,000,000 100,000 50,000
Maximum throughput of a single cloud disk (Mbit/s) 4,000 750 350
Performance formula for a single cloud disk IOPS = min{1800 + 50 * capacity, 1000000} IOPS = min{1800 + 50 * capacity, 100000} IOPS = min{1800 + 50 * capacity, 50000}
Throughput = min{120 + 0.5 * capacity, 4000} Mbit/s Throughput = min{120 + 0.5 * capacity, 750} Mbit/s Throughput = min{120 + 0.5 * capacity, 350} Mbit/s

Billing

ESSD cloud disks support Pay-As-You-Go and Subscription billing methods. For more information, see Create a Pay-As-You-Go cloud disk and Create a Subscription cloud disk.

For more information, see ECS products.

PL selection for ESSD cloud disks

ESSD cloud disks of the three PLs have the same single-disk capacity that ranges from 20 GiB to 32,768 GiB. The key difference lies in the maximum performance of a single disk. You can use ESSD cloud disks as system disks or data disks according to your specific needs. The scenarios where ESSD cloud disks are used as data disks are described as follows:

  • ESSD PL1 cloud disks are suitable for scenarios where moderate concurrent IOPS and stable read/write latency are required.

    Such scenarios include small and medium MySQL and SQLServer databases, ELK clusters, enterprise-level commercial software (such as SAP and Oracle), and container applications. In these scenarios, you can use ESSD PL1 cloud disks to replace SSD or Ultra cloud disks.

  • ESSD PL2 cloud disks are suitable for scenarios where high concurrent IOPS and stable read/write latency are required.

    Such scenarios include medium relational databases and NoSQL databases, ELK clusters, and enterprise-level commercial software (such as SAP and Oracle). In these scenarios, you can use ESSD PL2 cloud disks to replace SSD cloud disks or local SSD instance types (i1, i2, and i2g).

  • ESSD PL3 cloud disks are suitable for scenarios where ultra-high concurrent IOPS and ultra-stable read/write latency are required.

    Such scenarios include medium and large relational databases and NoSQL databases, and large enterprise-level commercial software (such as SAP and Oracle). In these scenarios, you can use ESSD PL3 cloud disks to replace local SSD instance types (specifically the instance types i1, i2, and i2g, with at least 16 vCPUs).

Disk capacity and performance

For ESSD cloud disks, larger capacity positively corresponds with higher data-processing performance. The capacity, IOPS, and throughput provided by ESSD cloud disks vary depending on their performance levels. The specific capacity and performance are detailed in the following table.
Performance level Capacity (GiB) Maximum IOPS Maximum throughput (Mbit/s)
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 you select 20 GiB memory when you create an ESSD cloud disk on the ECS console, you can only select a PL1 ESSD cloud disk whose maximum IOPS is 50,000.
  • Example 2: If you select 32,000 GiB memory, you can select an ESSD cloud disk of any performance level. The maximum IOPS is 50,000, 100,000, and 1000,000 in ascending order of the performance level.

If you require higher performance, resize the ESSD cloud disk or change the performance level of the ESSD cloud disk.

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