This topic describes the limits on ECS product features, service performance, and the method for applying for a higher quota.

Overview

The limits of ECS instances are as follows:

  • ECS does not support virtual application installation or revirtualization (such as installation of VMware Workstation). Currently, only ECS Bare Metal Instances and super computing clusters support revirtualization.
  • ECS does not support sound card applications.
  • ECS does not support external hardware devices (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. We recommend that you use 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 whether you can open a ticket to request changing the limits.

ECS instances

Item Limit Can I open a ticket to change the limit?
Permission to create instances Complete real-name registration before creating ECS instances in Mainland China regions. Real name registration is not required when creating instances outside Mainland China. No
Instance types for which you can create Pay-As-You-Go instances Instance types with less than 16 vCPUs Yes
vCPU quota of Pay-As-You-Go instances in each region for a single account

50 vCPUs

You can click Privileges & Quota Management on the Overview page of the ECS console to view the quota.

Yes
vCPU quota of preemptible instances in each region for a single account Up to 50 vCPUs are allowed after you open a ticket to obtain the permission.

You can click Privileges & Quota Management on the Overview page of the ECS console to view the quota.

Yes
Quota of launch templates in each region for a single account 30 No
Quota of versions of a single 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
  • Whether this feature is supported is based on your ECS instance resource usage.
  • 5,000 vCPUs*hours per month. For more information, see Conversion notes.
  • The maximum refund per month is limited, and is displayed on the switch page.
No

Block storage

Item Limit Can I open a ticket to change the limit?
Create Pay-As-You-Go cloud disks Complete real-name registration before creating cloud disks in any Mainland China regions. No
Quota of Pay-As-You-Go cloud disks in all regions for a single account Number of Pay-As-You-Go instances in all regions under the user account × 5 Yes
Quota of system disks for a single instance 1 No
Quota of data disks for a single instance 16 (including cloud disks and Shared Block Storage) No
Quota of instances to which a single Shared Block Storage can be attached 8 No
Quota of Shared Block Storage in all regions for a single account 10 Yes
Capacity of a single Basic Cloud Disk 5 GiB-2,000 GiB No
Capacity of a single SSD Cloud Disk 20 GiB-32,768 GiB No
Capacity of a single Ultra Cloud Disk 20 GiB-32,768 GiB No
Capacity of a single local SSD disk 5 GiB-800 GiB No
Capacity of local SSD disks for a single instance 1,024 GiB No
Capacity of a single local NVMe SSD disk 1,456 GiB No
Capacity of local NVMe SSD disks for a single instance 2,912 GiB No
Capacity of a single local SATA HDD disk 5,500 GiB No
Capacity of local SATA HDD disks for a single instance 154,000 GiB No
Capacity of a single SSD Shared Block Storage 32,768 GiB No
Capacity of SSD Shared Block Storage for a single instance 128 TiB No
Capacity of a single Ultra Shared Block Storage 32,768 GiB No
Capacity of Ultra Shared Block Storage for a single instance 128 TiB No
Capacity of a single ESSD disk 32,768 GiB No
Capacity of a single system disk
  • Windows: 40 GiB-500 GiB
  • Linux (excluding CoreOS) and FreeBSD: 20 GiB-500 GiB
  • CoreOS: 30 GiB-500 GiB
No
Capacity of a single 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 Limit Can I open a ticket to change the limit?
The number of snapshots that can be created for each cloud disk and Shared Block Storage 64 No

Images

Item Limit Can I open a ticket to change the limit?
Quota of custom images in a region for each account 100 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 Limit Can I open a ticket to change the limit?
Quota of key pairs in a region for each 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 Limit 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 a single 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 Limit on common security groups Limit on enterprise-level security groups
Number of security groups in a region for each account 100

You can view the quota on the Overview page of the ECS console. If you require a higher quota, open a ticket.

Same as common security groups.
Number of classic network instances that can be added to a classic network security group 1000* Classic network is not supported.
Number of VPC-connected instances that can be added to a VPC security group Depends on the number of private IP addresses supported by a security group. N/A
Number of security groups that an ECS instance can be added to 5

If you require a higher quota, open a ticket to increase the quota to 10 or 16.

Same as common security groups.
Number of security groups that each ENI of an ECS instance can be added to
Maximum number of rules that can be added for a security group (including inbound and outbound rules) 100*** Same as common security groups.
Maximum number of rules for an ENI in all the security groups that the ENI is added to (including inbound and outbound rules) 500 Same as common security groups.
Number of private IP addresses supported by a VPC security group 2000** N/A
Number of ENIs supported by a VPC security group Depends on the number of security group rules. 50000
Internet access port For the outbound Internet traffic, the default STMP port is 25, which is disabled by default and cannot be enabled by setting security group rules. For information about how to enable port 25, see . Same as common security groups.

*If more than 1000 classic network instances require intranet access, you can assign them to multiple security groups and authorize mutual access between these security groups by setting security group rules.

**If more than 2000 private IP addresses require intranet access, you can assign ECS instances corresponding to these private IP addresses to multiple security groups and authorize mutual access between these security groups by setting security group rules.

***Up to 500 security group rules can be added for an ECS instance. If you increase the quota of security groups that an ECS instance can be added to, the maximum number of rules for each security group will decrease. The number of security groups multiplied by the maximum number of inbound and outbound rules for each security group must be less than or equal to 500.

Deployment sets

Item Limit Can I open a ticket to change the limit?
Quota of deployment sets in a region for each account 2 No
Number of instances that can be included in a deployment set Up to seven instances are allowed in each zone. The number of instances allowed in a 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 a region for each account 100 Yes
Quota to invoke cloud assistant scripts in a region for each account 5000 Yes

ENIs

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

100

You can click Privileges & Quota Management on the Overview page of the ECS console to view the quota.

Yes

Tags

Item Limit Can I open a ticket to change the limit?
Quota of tags that can be bound to a single 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.