Alibaba Cloud enhanced SSDs (ESSDs) use 25 Gigabit Ethernet and remote direct memory access (RDMA) to reduce latency and deliver up to 1,000,000 random read/write IOPS per disk. This topic provides general information about ESSDs, such as performance levels (PLs), use 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{1800 + 50 × Capacity, 1,000,000} | min{1800 + 50 × Capacity, 100,000} | min{1800 + 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, 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 |
Billing methods
ESSDs support the pay-as-you-go and subscription billing methods.
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 databases
- NoSQL databases: non-relational databases such as MongoDB, HBase, and Cassandra databases
- Elasticsearch distributed logs: ELK log analysis
Capacity and PLs
| 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.
- 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.
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 g7se storage enhanced instance family, the higher the specifications of an instance type, the higher storage IOPS and throughput the instance can deliver. For more information, see Storage I/O 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, g7se is used:
- Example 1: Alex creates a 16 GiB instance of the ecs.g7se.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.g7se.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.g7se.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 family.