When using ECS, consider the following:

  • ECS does not support virtual application installation or subsequent virtualization such as when using VMware.  Currently, only ECS Bare Metal Instance and Super Computing Clusters supports virtualization.
  • ECS does not support sound card applications. 
  • ECS does not support the installation of external hardware devices such as hardware dongles, USB drives, external hard drives, and  the USB security keys issued by banks.
  • ECS does not support SNAT and other IP packet address translation services.  You can achieve this by using an external VPN or proxy.
  • ECS does not support multicast protocol.  If multicasting services are required, we recommend that you use unicast point-to-point method.
  • Currently, Log Service does not support 32-bit Linux ECS instance. To know the regions that support Log Service, see Service endpoint. To know the server operating systems that support Log Service, see Overview.

Besides the preceding limit, the additional limits of ECS are mentioned in the following table.

ECS instances

Item Limit Supply for higher configuration or unlock configuration rights
Permission to create instances  Complete real-name registration to create ECS instances in the mainland China regions Not supported
Default quota of Pay-As-You-Go ECS instances (including preemptible instances) in all regions for one account  10 Open a ticket
Launch templates in each region for one account 30 Not supported
Versions of one launch template 30 Not supported
Conversion of the billing method from Pay-As-You-Go to Subscription  Not supported in the following instance types or type families:
  • Generation II: n1, ne2, and e3
  • All instance types of Generation I
Not supported
Default available instance types for creating Pay-As-You-Go ECS instances (New generation) ecs.t1.small (1 vCPU core, 1 GiB)  Open a ticket
ecs.s1.small (1 vCPU core, 2 GiB)
ecs.s1.medium (1 vCPU core, 4 GiB)
ecs.s2.small (2 vCPU core, 2 GiB)
ecs.s2.large (2 vCPU core, 4 GiB)
ecs.s2.xlarge (2 vCPU core, 8 GiB)
ecs.s3.medium (4 vCPU core, 4 GiB)
ecs.s3.large (4 vCPU core, 8 GiB)
ecs.m1.medium (4 vCPU core, 16 GiB)
Default available instance types for creating Pay-As-You-Go ECS instances (Previous generation)  ecs.n1.tiny (1 vCPU core, 1 GiB) Open a ticket
ecs.n1.small (1 vCPU core, 2 GiB)
ecs.n1.medium (2 vCPU core, 4 GiB)
ecs.n1.large (4 vCPU core, 8 GiB)
ecs.n2.small (1 vCPU core, 4 GiB)
ecs.n2.medium (4 vCPU core, 8 GiB)
ecs.n2.large (4 vCPU core, 16 GiB)
ecs.e3.small (1 vCPU core, 8 GiB)
ecs.e3.medium (2 vCPU core, 16 GiB)

Block storage

Item  Limit Supply for higher configuration or unlock configuration rights
Permission to create Pay-As-You-Go cloud disks Complete real-name registration to create cloud disks in the mainland China regions  Not supported
Quota of Pay-As-You-Go cloud disks in all regions for one account  Five times of the number of Pay-As-You-Go instances in all regions under one account  Open a ticket
Quota of system disks for one ECS instance  1 Not supported
Quota of data disks for one ECS instance  16 (including cloud disks and Shared Block Storage)  Not supported
Multi-node attachment of shared block storage  8 Not supported
Quota of shared block storage in all regions for one account  10 Open a ticket
Capacity of one Basic Cloud Disk  5 GiB ~ 2,000 GiB  Not supported
Capacity of one SSD Cloud Disk  20 GiB ~ 32,768 GiB  Not supported
Capacity of one Ultra Cloud disk  20 GiB ~ 32,768 GiB  Not supported
Capacity of one ephemeral SSD disk  5 GiB ~ 800 GiB  Not supported
Capacity of ephemeral SSD disks on one ECS instance  1,024 GiB  Not supported
Capacity of one NVMe SSD local disk  1,456 GiB  Not supported
Capacity of NVMe SSD local disks on one ECS instance  2,912 GiB  Not supported
Capacity of one SATA HDD local disk  5,500 GiB  Not supported
Capacity of SATA HDD local disks on one ECS instance  154,000 GiB  Not supported
Capacity of one SSD Shared Block Storage device  32,768 GiB  Not supported
Capacity of SSD Shared Block Storage devices on one ECS instance  128 TiB  Not supported
Capacity of one Ultra Shared Block Storage device  32,768 GiB  Not supported
Capacity of Ultra Shared Block Storage devices on one ECS instance  128 TiB  Not supported
Size limit of one system disk  Windows: 40 GiB − 500 GiB   Linux (excluding CoreOS)+ FreeBSD: 20 GiB − 500 GiB   CoreOS: 30 GiB − 500 GiB Not supported
Size limit of one data disk  Basic Cloud Disk: 5 GiB − 2,000 GiB   SSD Cloud Disk/Ultra Cloud Disk/SSD Shared Block Storage/Ultra Shared Block Storage: 20 GiB − 32,768 GiB  Local disk: See Local disks. Not supported
Attaching an independent local disk to an ECS instance with local disks  Not supported Not supported
Configuration changes of an ECS instance with local disks  Only changes to public network bandwidth are permitted  Not supported
Mount point for system disks  /dev/xvda Not supported
Mount points for data disks  /dev/xvd[b-z] Not supported

Snapshots

Item Limit  Supply for higher configuration or unlock configuration rights
Quota of snapshots  Number of elastic block storage devices * 64  Not supported

Images

Item Limit  Supply for higher configuration or unlock configuration rights
Quota of custom images in all regions for one account  100 Open a ticket
Quota of accounts to share one custom image  100 Open a ticket
Requirements of images for instance types  32-bit images are not supported on an instance with 4 GiB or more RAM.  Not supported

Key pairs

Item Limit  Supply for higher configuration or unlock configuration rights
Quota of key pairs in all regions for one account  500 Not supported
Instance types supporting key pairs  All instance types, except those non-I/O optimized instance types in Generation I  Not supported
Images supporting key pairs  Linux images only  Not supported

Security groups

Item Limit  Supply for higher configuration or unlock configuration rights
Quota of ECS instances for one security group  1,000  Not supported
Quota of rules for one security groups  100 Not supported
Quota of security groups in all regions for one account 

100

Open a ticket
Quota of security groups for one ECS instances  5 Open a ticket
Port Access to TCP Port 25, which is the default port for the STMP service, is denied. It cannot be allowed by adding a security group rule.  Open a ticket. For more information, see Apply to open TCP port 25

ENI

Item Limit  Supply for higher configuration or unlock configuration rights
Quota of ENI in one region for one account 

100

Open a ticket

Tags

Item Limit  Supply for higher configuration or unlock configuration rights
Quota of tags for one ECS instance  20 Not supported

API

Item Limit  Supply for higher configuration or unlock configuration rights
Invocation quota of CreateInstance  At most 200 times per minute  Open a ticket
Note
For more information about the limits for VPC, see Limits.