This topic provides general information about Alibaba Cloud enhanced SSDs (ESSDs), such as performance levels, usage scenarios, and performance specifications. ESSDs are provisioned on a 25GE network and based on the remote direct memory access (RDMA) technology. Each ESSD can deliver up to 1,000,000 random IOPS with low latency.
Scenarios
Enhanced SSDs feature low latency, fast response, and high data throughput. They are ideal for latency-sensitive applications or I/O intensive business scenarios, for example:
- Online transaction processing (OLTP) databases: relational databases, such as MySQL, PostgreSQL, Oracle, and SQL Server databases
- NoSQL databases: non-relational databases, such as MongoDB, HBase, and Cassandra databases
- Real-time analysis applications: Elasticsearch distributed log analysis, Elasticsearch, Logstash, and Kibana (ELK) log analysis
Specifications
The API parameter value cloud_essd indicates ESSDs. ESSDs are divided into three performance levels (PLs) based on the maximum performance per disk.
| Property of ESSDs | Performance level 3 | Performance level 2 | Performance level 1 |
|---|---|---|---|
| PL | PL3 | PL2 | PL1 |
| 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 |
| Capacity (GiB) | 1,261~32,768 | 461~32,768 | 20~32,768 |
| Data reliability | 99.9999999% | 99.9999999% | 99.9999999% |
| Maximum input/output operations per second (IOPS) per disk | 1,000,000 | 100,000 | 50,000 |
| Maximum throughput per disk (MB/s) | 4,000 | 750 | 350 |
| 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} |
| 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} |
| Products where ESSDs are recommended to be used or disks that can be replaced with ESSDs | Instance families with local SSDs and 16 or more vCPUs (i1, i2, and i2g) | Instance families with local SSDs (i1, i2, and i2g) | Standard SSDs and ultra disks |
| Example scenario | Large and medium-sized relational databases for core businesses and NoSQL databases, and large SAP and Oracle databases | Medium-sized relational databases and NoSQL databases, medium-sized 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 |
Billing methods
Enhanced SSDs support pay-as-you-go and subscription billing methods. For more information, see Create a pay-as-you-go disk and Create a subscription disk.
For information about the pricing of ESSDs at different performance levels, click the Pricing tab of the Elastic Compute Service page.
Capacity and performance levels of ESSDs
| Performance level | Capacity of ESSDs (GiB) | Maximum IOPS | Maximum throughput (MB/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 Alex selects 20 GiB of storage capacity when he creates ESSD in the
ECS console, PL1 is the only available option. Each PL1 ESSD has a maximum IOPS of
50,000.
- Example 2: If Alex selects 32,000 GiB of storage capacity, PL1-PL3 levels are available.
The maximum IOPS for PL1 is 50,000, PL2 is 100,000, and PL3 is 1,000,000.
Storage I/O performance of instance types
The storage I/O performance of some new-generation instance families is proportional to the instance specifications.
The following examples show you how instance types and performance specifications of attached ESSDs determine the maximum IOPS of instances.
- Example 1: Alex creates a 16 GiB instance of the ecs.g5se.xlarge instance type. The maximum IOPS of this instance type is 60,000. Alex then attaches to the instance an ESSD whose capacity is 1,800 GiB and maximum IOPS is 100,000. The 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.g5se.4xlarge instance type. The maximum IOPS of this instance type is 230,000. Alex then attaches to the instance an ESSD whose capacity is 1,800 GiB and maximum IOPS is 100,000. The maximum IOPS of the instance is 100,000, because it is no longer limited by the maximum IOPS of the instance type, but is instead limited by the maximum IOPS of the ESSD.
Related operations
| Business need | Documentation | Related API operation |
|---|---|---|
| Create an ESSD separately and use it as a data disk | CreateDisk | |
| Change billing methods | Convert the billing method of a cloud disk | ModifyDiskChargeType |
| Attach a pay-as-you-go data disk to an ECS instance | Attach a data disk | AttachDisk |
| Create a normal or local snapshot | Create a normal snapshot | CreateSnapshot |
| Increase the capacity of an ESSD | Overview | ResizeDisk |
| Resize an ESSD to improve performance | ||
| Detach a pay-as-you-go data disk | Detach a data disk | DetachDisk |
| Release a data disk separately | Release a disk | DeleteDisk |