When using ECS, note the following limitations:

  • ECS does not support virtual application installation or revirtualization (such as installation of VMware). Currently, only ECS Bare Metal Instance and Super Computing Clusters support revirtualization.
  • ECS does not support sound card applications.
  • ECS does not support external hardware devices directly (such as dongles, USB drives, or external hard drives). Instead, it supports a software protection dongle or two-step verification with dynamic passwords.
  • ECS does not support IP address translation services such as SNAT. Instead, it supports a VPN or proxy.
  • ECS does not support multicast protocols. If multicasting services are required, we recommend that you use point-to-point unicast instead.
  • Currently, Log Service does not support 32-bit Linux ECS instances. For information about regions that support Log Service, see Service endpoint. For information about operating systems that support Log Service, see Overview.

In addition to the preceding limits, the following table details further limits of ECS and states whether you can open a ticket to request changing the limits.

ECS instances

Item Limitation Can I open a ticket to change the limitation?
Permission to create instances Complete real-name registration before creating ECS instances in any mainland China regions. No
Instance types for which you can create Pay-As-You-Go instances Instance types with less than 16 vCPUs Yes
Default quota of Pay-As-You-Go instances in each region for one account 50 vCPUs (increases with membership levels) Yes
Default quota of preemptible instances in each region for one account Up to 50 vCPUs are allowed after the permission is granted. The quota increases with membership levels. Yes
Default quota of launch templates in each region for one account 30 No
Default quota of versions of one launch template 30 No
Switch from Pay-As-You-Go to Subscription The following instance types (families) are not supported: t1, s1, s2, s3, c1, c2, m1, m2, n1, n2, and e3. No
Switch from Subscription to Pay-As-You-Go
  • Depends on the membership level
  • 5,000 vCPUs × hours for each month. The quota increases with membership levels.
  • Maximum refund limit per month (varies with the membership level).
 No

Block storage

Item Limitation Can I open a ticket to change the limitation?
Create Pay-As-You-Go cloud disks Complete real-name registration before creating cloud disks in any Mainland China regions. No
Default quota of Pay-As-You-Go cloud disks in all regions for one account Number of Pay-As-You-Go instances in all regions under the user account × 5 Yes
Default quota of system disks for one instance 1 No
Default quota of data disks for one instance 16 (including cloud disks and Shared Block Storage) No
Default quota of instances to which one Shared Block Storage can be attached 8 No
Default quota of Shared Block Storage in all regions for one account 10 Yes
Capacity of one Basic Cloud Disk 5 GiB−2,000 GiB No
Capacity of one SSD Cloud Disk 20 GiB−32,768 GiB No
Capacity of one Ultra Cloud disk 20 GiB−32,768 GiB No
Capacity of one local SSD disk 5 GiB−800 GiB No
Capacity of local SSD disks for one instance 1,024 GiB No
Capacity of one local NVMe SSD disk 1,456 GiB No
Capacity of local NVMe SSD disks for one instance 2,912 GiB No
Capacity of one local SATA HDD disk 5,500 GiB No
Capacity of local SATA HDD disks for one instance 154,000 GiB No
Capacity of one SSD Shared Block Storage 32,768 GiB No
Capacity of SSD Shared Block Storage for one instance 128 TiB No
Capacity of one Ultra Shared Block Storage 32,768 GiB No
Capacity of Ultra Shared Block Storage for one instance 128 TiB No
Capacity of one ESSD disk 32,768 GiB No
Capacity of one system disk
  • Windows: 40 GiB−500 GiB
  • Linux (excluding CoreOS) and FreeBSD: 20 GiB−500 GiB
  • CoreOS: 30 GiB−500 GiB
 No
Capacity 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: dependent on specific disks
 No
Attach a new local disk to an instance with local disks This feature is not supported. No
Change configuration of an instance with local disks Only bandwidth changes are allowed. No
System disk mount points /dev/xvda No
Data disk mount points /dev/xvd[b-z] No
Note Block storage capacity is measured in binary units. 1 KiB is 1,024 bytes. 1 MiB is 1,024 KiB. 1 GiB is 1,024 MiB. 1 TiB is 1,024 GiB.

Snapshots

Item Limitation Can I open a ticket to change the limit?
Quota of snapshots Each cloud disk and Shared Block Storage can have up to 64 snapshots No

Images

Item Limitation Can I open a ticket to change the limit?
Quota of custom images in one region for one account 100 (increases with membership levels) Yes
Maximum number of users with whom a single image can be shared 50 Yes
Usage of images on instance types 32-bit images are not supported on an instance with 4 GiB or more RAM. No

Key pairs

Item Limitation Can I open a ticket to change the limit?
Quota of key pairs in one region for one account 500 No
Instance types supporting key pairs All instance types except non-I/O optimized instance types in Generation I No
Images supporting key pairs Linux images only No

Internet bandwidth

Item Limitation Can I open a ticket to change the limit?
Maximum inbound Internet bandwidth 200 Mbit/s No
Maximum outbound Internet bandwidth
  • Subscription instance: up to 200 Mbit/s
  • Pay-As-You-Go instance: up to 100 Mbit/s
 No
Change the assigned Internet address for one instance The instance has existed for less than six hours. You can change the Internet address of an instance three times. No

Security groups

Item Limitation Can I open a ticket to change the limit?
Quota of security groups in one region for an account

100 (increases with membership levels)

 Yes
Quota of instances/IP addresses for one security group
  • Security groups for classic network instances: 1,000 classic network instances
  • Security groups for VPC instances: 2,000 private IP addresses (shared by primary and secondary network cards)
No
Quota of security groups to which each Elastic Network Interface (ENI) belongs for one instance 500 No
Quota of security groups to which each Elastic Network Interface (ENI) belongs for one instance 5 Open a ticket to raise the upper limit to 10 or 16
Quota of rules for one security group 100 No It decreases as the security group quota increases. For detailed restrictions, see Security groups
Port For the outbound Internet traffic, the default STMP port is 25, which is disabled by default and cannot be enabled through security group rules. Open a ticket to enable it. For more information, see Request for enabling TCP port 25

Deployment sets

Item Limit Can I open a ticket to change the limit?
Quota of deployment sets in one region for an account 2 No
The number of instances that can be included in a deployment set Seven instances are allowed in one zone. The number of instances allowed in one region equals the number of zones × 7. No
Instance types that can be created in a deployment set c5, g5, hfc5, hfg5, r5, se1ne, sn1ne, and sn2ne No

Cloud assistants

Item Limit Can I open a ticket to change the limit?
Quota of cloud assistant scripts in one region for one account 100 Yes
Quota to invoke cloud assistant scripts in one region for one account 500 Yes

ENIs

Item Limit Can I open a ticket to change the limit?
Quota of ENIs in one region for one account

100 (increases with membership levels)

 Yes

Tags

Item Limit Can I open a ticket to change the limit?
Quota of tags that can be bound to one instance 20 No

API

Item Limit Can I open a ticket to change the limit?
Quota of CreateInstance calls 200 times per minute Yes
Note For the limits of VPC products, see Limits.