ECS Types

ECS Flavor Naming Rules

ECS flavors are named in the "AB.C.D" format.

Example: s2.medium.4

The format is defined as follows:

• A indicates the instance family. For example, s indicates general computing, c indicates general computing-plus, and m indicates memory-optimized.
• B indicates the instance generation. For example, 3 in s3 indicates the general computing III generation.
• C indicates the instance size, such as medium, large, xlarge, 2xlarge, 4xlarge, and 8xlarge.
• D indicates the ratio of memory to vCPUs expressed in a digit. For example, value 4 indicates that the ratio of memory to vCPUs is 4.

How Do I Know My ECS Flavor?

When creating an ECS, you can view the flavors in the flavor list.

Figure 1 ECS flavors

vCPU

ECS supports hyper-threading, which enables two threads to run concurrently on a single CPU core. Each thread is represented as a virtual CPU (vCPU). When hyper-threading is enabled, each CPU core contains two vCPUs available to your workloads.

For example, a 2-core physical CPU contains 4 vCPUs (threads).

Hyper-threading is enabled for most ECS flavors by default. If hyper-threading is disabled during the ECS creation or flavor change, the number of vCPUs is half of the number of vCPUs defined by the ECS flavor.

Network QoS

Network QoS uses basic technologies to improve the quality of network communication. A network with QoS enabled offers predictable network performance and effectively allocates network bandwidth.

For details about the QoS data of an ECS flavor, including the maximum/assured network bandwidth (Gbit/s), maximum network PPS, and maximum NIC queues, see A Summary List of ECS Specifications.

Constraints on network performance vary depending on ECS flavors.

• Assured network bandwidth: indicates the guaranteed bandwidth allocated to an ECS when there is a network bandwidth contention in the entire network.
• Maximum network bandwidth: indicates the maximum bandwidth that can be allocated to an ECS when the ECS does not compete for network bandwidth (other ECSs on the host do not have high requirements on network bandwidth).
• Maximum network PPS: indicates the maximum number of packets that an ECS can transmit and receive per second.

  Packets per second (PPS): indicates the number of packets received and sent per second. It is usually used to measure the network performance.

• NIC multi-queues: allocates NIC interruptions to multiple vCPUs for higher PPS performance and bandwidth
• Maximum NICs: indicates the maximum number of NICs that can be attached to an ECS.

• For instructions about how to test PPS, see How Can I Test the Network Performance of Linux ECSs?
• For instructions about how to enable NIC multi-queue, see Enabling NIC Multi-Queue.
• The maximum bandwidth is the total bandwidth allocated to an ECS. If an ECS has multiple NICs, the sum of the maximum bandwidths allocated to all NICs cannot exceed the maximum bandwidth allocated to the ECS.