When using ECS, note the following limitations:

  • ECS instances do not support virtual application installation or revirtualization (such as installation of VMware). Currently, only ECS Bare Metal Instance and Super Computing Clusters supports revirtualization.
  • ECS instances do not support sound card applications.
  • You cannot mount external hardware devices directly (such as hardware dongles, USB drives, external hard drives, and the USB security keys issued by banks). Instead, use a software protection dongle or two-step verification with dynamic passwords.
  • ECS does not support IP packet address translation services such as SNAT. Instead, use 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 limitations, the following table details further limitations of ECS and states whether you can submit a ticket to request changing the limitation.

ECS instances

Item Limitation Can I open a ticket to raise 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 once 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, e3 No

Block storage

Item Limitation Can I open a ticket to raise 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
Quota of system disks for one instance 1 No
Quota of data disks for one instance 16 (including cloud disks and Shared Block Storage)  No
Quota of instances to which one shared block storage can be attached 8 No
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 allowed No
System disk mount points /dev/xvda No
Data disk mount points /dev/xvd[b-z] No

Snapshots

Item Limitation Can I open a ticket to raise the limitation?
Quota of snapshots Number of elastic block storage devices × 64 No

Images

Item Limitation Can I open a ticket to raise the limitation?
Quota of custom images in all regions 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 raise the limitation?
Quota of key pairs in all regions for one account 500 No
Instance types supporting key pairs All instance types except for 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 raise the limitation?
Maximum inbound Internet bandwidth 200 Mbit/s No
Maximum outbound Internet bandwidth 100 Mbit/s Yes. Note that you can increase the limit up to 200 Mbit/s only.
Change the assigned public IP address for one instance The instance has existed for less than six hours. You can change the public IP address of an instance three times. No

Security group

Item Limitation Can I open a ticket to raise the limitation?
Quota of instances/IP for one security group
  • Security groups for classic network instances: 1,000 classic network instances
  • Security groups for VPC instances: 2,000 private IP (shared by primary and secondary network cards)
No
Quota of authorization rules for one security group 100 No
Quota of security groups in a region for an account

100 (increases with membership levels)

 Yes
Quota of security groups to which each elastic network interface belongs for one instance 5 Yes
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. Yes. For more information, see Request for enabling TCP port 25.

ENI

Item Limitation Can I open a ticket to raise the limitation?
Quota of ENIs in one region for one account

100 (increases with membership levels)

 Yes

Label

Item Limitation Can I open a ticket to raise the limitation?
Quota of tags that can be bound to one instance 20 No

API

Item Limitation Can I open a ticket to raise the limitation?
Quota of CreateInstance calls 200 times per minute Yes
Note For more information about limitations of VPC products, see Limits.