This topic describes service limits of ECS and how to request exceptions to the limits.

Overview

ECS has the following service limits:

  • ECS does not allow you to install virtualization software, such as VMware Workstation, or use it for re-virtualization. Only ECS Bare Metal Instances and Super Computing Clusters support re-virtualization.
  • ECS does not support sound card applications.
  • External hardware devices, such as hardware dongles, USB flash drives, external hard disks, and hardware tokens, cannot be attached. Software verification methods such as two-factor authentication and dynamic passwords can be used.
  • ECS does not support IP address translation services such as SNAT. Instead, it achieves this function by using VPNs and proxies.
  • ECS does not support multicast protocols. We recommend that you use unicast instead.
  • 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 the Overview section about Logtail collection.

View quotas

On the Overview page of the ECS console, click Privileges & Quotas and select a region to view the resource quotas in that region. If the quota of a resource cannot meet your needs, submit a ticket to request an increase for the quota. For more information, see Manage privileges and quotas. You can also view resource quotas by calling an API operation. For more information, see DescribeAccountAttributes.

Instance limits

Item Limit Request an exception to a limit
Permissions to create instances To create ECS instances in any Mainland China regions, you must first complete real-name authentication. No exceptions
Instance types for which you can create pay-as-you-go instances Instance types with less than 16 vCPUs. Submit a ticket
Total number of vCPUs of pay-as-you-go instances in each region for an account 50 vCPUs Submit a ticket
Total number of vCPUs of preemptible instances in each region for an account 0 vCPUs. You can submit a ticket to request the quota of 50 vCPUs. Submit a ticket
Total number of launch templates in each region for an account 30 No exceptions
Total number of versions of a launch template 30 No exceptions
Switch from pay-as-you-go to subscription Not supported by the following instance types (families): t1, s1, s2, s3, c1, c2, m1, m2, n1, n2, and e3. No exceptions
Switch from subscription to pay-as-you-go
  • Whether this feature is supported depends on your ECS instance resource usage.
  • 5,000 vCPU hours each month.
  • A maximum monthly refund limit is set. For more information about the refund limit, see the Switch to Pay-As-You-Go page.
No exceptions

Block Storage limits

Item Limit Request an exception to a limit
Permissions to create pay-as-you-go disks Complete real-name authentication before creating disks in any Mainland China regions. No exceptions
Total number of all pay-as-you-go disks in all regions for an account Number of pay-as-you-go instances in all regions for an account × 5. Each account can create at least 10 pay-as-you-go disks. Submit a ticket
Total number of system disks for each instance 1 No exceptions
Maximum number of data disks for an instance 16 (including disks and Shared Block Storage devices) No exceptions
Number of instances to which a Shared Block Storage device can be attached 8 No exceptions
Total number of Shared Block Storage devices in all regions for an account 10 Submit a ticket
Capacity of a basic disk 5 GiB to 2,000 GiB No exceptions
Capacity of a standard SSD 20 GiB to 32,768 GiB No exceptions
Capacity of an ultra disk 20 GiB to 32,768 GiB No exceptions
Capacity of a local SSD 5 GiB to 800 GiB No exceptions
Total capacity of all local SSDs for an instance 1,024 GiB No exceptions
Capacity of a local NVMe SSD 1,456 GiB No exceptions
Total capacity of all local NVMe SSDs for an instance 2,912 GiB No exceptions
Capacity of a local SATA HDD 5,500 GiB No exceptions
Total capacity of all local SATA HDDs for an instance 154,000 GiB No exceptions
Capacity of an SSD Shared Block Storage device 32,768 GiB No exceptions
Total capacity of all SSD Shared Block Storage devices for an instance 128 TiB No exceptions
Capacity of an ultra Shared Block Storage device 32,768 GiB No exceptions
Total capacity of all ultra Shared Block Storage devices for an instance 128 TiB No exceptions
Capacity of an enhanced SSD (ESSD) 32,768 GiB No exceptions
Capacity of a system disk
  • Windows: 40 GiB to 500 GiB
  • Linux (excluding CoreOS) and FreeBSD: 20 GiB to 500 GiB
  • CoreOS: 30 GiB to 500 GiB
No exceptions
Capacity of a data disk
  • Basic disk: 5 GiB to 2,000 GiB
  • standard SSD, ultra disk, SSD Shared Block Storage device, or ultra Shared Block Storage device: 20 GiB to 32,768 GiB
  • Local disk: dependent on specific disks
No exceptions
Attach new local disks to instances that have local disks Not supported No exceptions
Change the specifications of instances that have local disks Only bandwidth can be changed No exceptions
System disk mount points /dev/xvda No exceptions
Data disk mount points /dev/xvd[b-z] No exceptions
Note Block storage capacity is measured in binary units. 1 KiB equals 1,024 Bytes. 1 GiB equals 1,024 MiB.

Snapshot limits

Item Limit Request an exception to a limit
Number of snapshots that can be created for each disk and Shared Block Storage device 64 No exceptions
Number of automatic snapshot policies that can be created in a region for an account 100 No exceptions

Image limits

Item Limit Request an exception to a limit
Total number of custom images in each region for an account 100 Submit a ticket
Maximum number of users with whom an image can be shared 50 Submit a ticket
Images supported by instance types Instance types that have 4 GiB or more memory do not support 32-bit images. No exceptions

SSH key pair limits

Item Limit Request an exception to a limit
Total number of SSH key pairs in each region for an account 500 No exceptions
Instance types supporting SSH key pairs All instance types except non-I/O optimized instance types in Generation I No exceptions
Images supporting SSH key pairs Linux images only No exceptions

Public bandwidth limits

Item Limit Request an exception to a limit
Maximum inbound public bandwidth 200 Mbit/s No exceptions
Maximum outbound public bandwidth
  • Subscription: up to 200 Mbit/s
  • Pay-as-you-go: up to 100 Mbit/s
No exceptions
Change the assigned public IP address for an instance Public IP addresses can be changed within six hours after the instance is created, and can be changed a maximum of three times. No exceptions

Security group limits

Item Limit on basic security groups Limit on advanced security groups
Total number of security groups in each region for an account 100 Same as that on basic security groups.
Number of classic network-type ECS instances that can be added to a classic network-type security group 1,000* Classic network is not supported.
Number of VPC-type ECS instances that can be added to a VPC-type security group Depends on the number of private IP addresses in a VPC-type security group. No limit.
Number of security groups that can contain the same ECS instance 5

You can submit a ticket to raise the limit to 10 or 16 security groups.

Same as that on basic security groups.
Number of security groups that can contain the same ENI of an ECS instance
Maximum number of rules (both inbound and outbound) in a security group 100*** Same as that on basic security groups.
Maximum number of rules (both inbound and outbound) in all security groups that contain the same ENI 500 Same as that on basic security groups.
Number of private IP addresses in a VPC-type security group 2,000** No limit.
Number of ENIs in a VPC-type security group Depends on the maximum number of rules in a security group. 50,000.
Public network access port The default STMP port for outbound traffic is port 25, which is disabled by default. It cannot be enabled by security group rules. Same as that on basic security groups.

* If more than 1,000 classic network-type instances need access to each other, you can distribute them across multiple security groups and authorize mutual access.

** If you require mutual access among more than 2,000 private IP addresses, you can distribute them across multiple security groups and authorize mutual access.

*** If you increase the number of security groups that can contain the same ECS instance, the maximum number of rules in a security group will decrease. The product of the number of security groups that can contain the same ECS instance and the maximum number of rules (both inbound and outbound) in a security group must be less than or equal to 500. For example, 5 × 100 = 500, 10 × 50 = 500, and 16 × 30 < 500.

Deployment set limits

Item Limit Request an exception to a limit
Total number of deployment sets in each region for an account 2 No exceptions
Total number of instances that can be included in a deployment set Seven instances are allowed in a zone. The maximum number of instances allowed in a region is 7 × number of zones. No exceptions
Instance types that can be created in a deployment set c5, g5, hfc5, hfg5, r5, se1ne, sn1ne, and sn2ne No exceptions

Cloud Assistant limits

Item Limit Request an exception to a limit
Total number of Cloud Assistant commands in each region for an account 100 Submit a ticket
Total number of Cloud Assistant commands that can be used by an account each day in a region 5,000 Submit a ticket

ENI limits

Item Limit Request an exception to a limit
Total number of ENIs in each region for an account 100 Submit a ticket

Tag limits

Item Limit Request an exception to a limit
Total number of tags that can be bound to an instance 20 No exceptions

API limits

Item Limit Request an exception to a limit
Total number of CreateInstance calls 200 calls per minute Submit a ticket
Note For more information about the VPC limits, see Limits.