This topic answers frequently asked questions about the performance of Alibaba Cloud Edge Node Service (ENS).
ENS network capabilities
ENS nodes reach the ISP backbone network within 4 hops from the node egress. Users in the same region experience less than 5 ms average latency to the nearest edge node.
The packet loss rate for traffic from an ENS node to a monitoring node on the same ISP within the same or a neighboring province is ≤ 1%. Rates for the Xinjiang and Xizang regions are subject to a separate agreement.
The DescribePrice API has a user-level limit of 20 QPS (queries per second). This rate is generally sufficient for typical usage. If you require a higher limit, contact support for an evaluation. Generally, creation APIs are limited to 10 QPS, and management and query APIs are limited to 50 QPS.
Maximum network card queues
ENS supports a maximum of 32 network card queues. This setting can be configured only during instance creation and cannot be changed afterward.
Disk load imbalance and performance
The underlying ENS physical disks have the same performance characteristics. In this case, volumes B and C share a single physical disk, while volume A has a dedicated one. Certain instance types run on physical servers with only two SSDs, which forces two logical volumes to share a single physical disk. As a result, the physical disk shared by volumes B and C handles twice the I/O requests compared to the disk for volume A, resulting in double the load.
Cloud-init support
ENS does not support cloud-init.
Uploading custom images
The ENS console does not support custom image uploads. If you must upload a custom image for special reasons, you must provide the operating system, its version, and the image in qcow2 format. Because the ENS platform must be adapted for unofficial public images, successful adaptation is not guaranteed.
We recommend creating custom images based on the official public images provided by ENS. After creation, the new image is automatically saved to your custom image library.
System disk partition auto-expansion
If the system disk of a Linux instance is larger than the original image size, extend the partition and file system manually. For instructions, see Extend partitions and file systems.