This topic describes the limits of ECS, and how to apply for extensions on certain limits.

Overview

ECS has the following limits:

  • You cannot install virtualization software such as VMware Workstation or use it for secondary virtualization. Only ECS bare metal instances and Super Computing Clusters (SCCs) support secondary 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 directly attached to ECS. Software verification methods such as two-factor authentication and dynamic passwords can be used.
  • ECS does not support multicast protocols. We recommend that you use unicast transmission instead.
  • Log Service does not support 32-bit Linux ECS instances.

    For information about the ECS instances that support Log Service, see Logtail overview.

  • If you need to apply for ICP filings for websites deployed on your ECS instance, the instance must meet certain purchase requirements. You can apply for a limited number of ICP filing service numbers for websites that are deployed on each ECS instance. For more information, see Prepare and check the instance and access information. For information about how to apply for ICP filings, see ICP filing application overview.

View quotas

You can click Privileges on the Overview page of the ECS console, and select a region to view the resource usage and quotas in that region. If the quota of a resource is insufficient, submit a ticket to apply for an increased quota. For more information about how to view privileges and quotas, see View and increase quotas (new version) or DescribeAccountAttributes.

Instance limits

Item Limit How to apply for an extension on the limit
Permissions to create an ECS instance To create an ECS instance in regions within mainland China, you must first complete real-name verification. None.
Instance types whose instances can be used as pay-as-you-go instances Instance types with less than 16 vCPUs. Submit a ticket.
Quota for vCPUs of all pay-as-you-go instances in each region for an account 50 vCPU. Submit a ticket.
Quota for vCPUs of all preemptible instances in each region for an account Submit a ticket to apply for the quota, which is up to 50 vCPUs. Submit a ticket.
Quota for instance launch templates in each region for an account 30. None.
Quota for versions of an instance launch template in each region for an account 30. None.
Permissions to switch the billing method from pay-as-you-go to subscription The following instance types (families) do not support billing method switching: t1, s1, s2, s3, c1, c2, m1, m2, n1, n2, and e3. None.
Permissions to switch the billing method from subscription to pay-as-you-go
  • Whether this feature is supported depends on your ECS usage.
  • 5,000 vCPUs × Number of hours per month.
  • Switching the billing method may result in a refund. Each account is limited to a maximum monthly refund amount. For more information, see Switch the billing method from subscription to pay-as-you-go.
None.

Reserved instance limits

Item Limit How to apply for an extension on the limit
Quota for regional reserved instances of an account 20 Submit a ticket.
Quota for zonal reserved instances of an account in a zone 20 Submit a ticket.
Instance types that support reserved instances Instance families that support reserved instances include:
  • Compute optimized instance families: c6e, c6, c5, ic5, and sn1ne
  • General purpose instance families: g6e, g6, g5, and sn2ne
  • Memory optimized instance families: r6e, r6, r5, and se1ne
  • Instance families with local SSDs: i2 and i2g
  • Instance families with high clock speed: hfc6, hfc5, hfg6, hfg5, and hfr6
  • Compute optimized instance families with GPU capabilities: gn6i and gn6e
  • ECS Bare Metal Instance families: ebmc6, ebmg6, ebmr6, ebmhfc6, ebmhfg6, and ebmhfr6
  • Burstable instance families: t6 and t5
Note The t5 instance family supports only zonal reserved instances.
None.
Note For more information, see the "Limits" section in Reserved instance overview.

Block Storage limits

Item Limit How to apply for an extension on the limit
Permissions to create a pay-as-you-go disk You must complete real-name verification before you can create a disk in regions within mainland China. None.
Quota for 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. The minimum upper limit of data disks in each account is ten disks. Submit a ticket.
Maximum capacity of pay-as-you-go disks that are used as data disks for an account This limit is subject to ECS resource usage, region, and disk category. You can go to the Privileges & Quotas page in the ECS console to view this information. For more information, see View and increase quotas (new version). Submit a ticket.
Quota for system disks of each instance 1. None.
Quota for data disks of each instance 16. None.
Capacity of a basic disk 5 GiB-2,000 GiB. None.
Capacity of a standard SSD 20 GiB-32,768 GiB. None.
Capacity of an ultra disk 20 GiB-32,768 GiB. None.
Capacity of an enhanced SSD (ESSD) 20 GiB-32,768 GiB. None.
Capacity of a local SSD 5 GiB-800 GiB. None.
Total capacity of all local SSDs for an instance 1,024 GiB. None.
Capacity of a local NVMe SSD 1,456 GiB. None.
Total capacity of all local NVMe SSDs for an instance 2,912 GiB. None.
Capacity of a local SATA HDD 5,500 GiB. None.
Total capacity of all local SATA HDDs for an instance 154,000 GiB. None.
Capacity of a system disk
  • Windows Server: 40 GiB to 500 GiB
  • CoreOS and FreeBSD: 30 GiB to 500 GiB
  • Linux systems excluding CoreOS: 20 GiB to 500 GiB
None.
Permission to attach new local disks to instances that are equipped with local disks Not allowed. None.
Permissions to change specifications of instances that are equipped with local disks Only bandwidth can be changed. None.
System disk mount points /dev/vda. None.
Data disk mount points /dev/vd[b-z]. None.
Note Block storage capacity is measured in binary units. In binary units, 1 KiB equals 1,024 bytes. Example: 1 GiB = 1,024 MiB.

Snapshot limits

Item Limit How to apply for an extension on the limit
Quota for manual snapshots that can be created for each disk 256 None
Quota for automatic snapshots that can be created for each disk or 1,000 None
Quota for automatic snapshot policies that can be created in a region for an account 100 None

Image limits

Item Limit How to apply for an extension on the limit
Quota for custom images that can be created in each region for an account 100 Submit a ticket.
Quota for users to whom a single image can be shared 50 Submit a ticket.
Restrictions on images and instance types Instance types that have 4 GiB or larger memory do not support 32-bit images. None.

SSH key pair limits

Item Limit How to apply for an extension on the limit
Quota for SSH key pairs in each region for an account 500 None
Instance types that support SSH key pairs Non-I/O optimized instances of Generation 1 instance families do not support SSH key pairs None
Images that support SSH key pairs Only Linux images None

Public bandwidth limits

Item Limit How to apply for an extension on the limit
Peak inbound bandwidth
  • If the purchased peak outbound bandwidth is less than or equal to 10 Mbit/s, Alibaba Cloud will allocate an inbound bandwidth of 10 Mbit/s.
  • If the purchased peak outbound bandwidth is greater than 10 Mbit/s, Alibaba Cloud will allocate an inbound bandwidth that is equal to the purchased peak outbound bandwidth.
None
Peak outbound bandwidth
  • Subscription: 200 Mbit/s
  • Pay-as-you-go: 100 Mbit/s
None
Change in the assigned public IP address of an instance The public IP address can be changed within six hours of the instance being created and can be changed a maximum of three times. None

Security group limits

Item Basic security group Advanced security group
Quota for security groups that can be created in each region for an account 100 Same as the limit on basic security groups.
Quota for classic network-type ECS instances that can be included in a classic network-type security group 1,000 The classic network is not supported.
Quota for VPC-type ECS instances that can be included in a VPC-type security group Depends on the number of private IP addresses that can be included in the VPC-type security group. No limits.
Quota for security groups to which an ECS instance can belong 5

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

Same as the limit on basic security groups.
Quota for security groups to which an ENI of an ECS instance can belong
Quota for rules (both inbound and outbound) in a security group 200 Same as the limit on basic security groups.
Quota for rules (both inbound and outbound) in all security groups to which an ENI belongs 1,000 Same as the limit on basic security groups.
Quota for private IP addresses that can be included in a VPC-type security group 2,000 65,536.
Public network access port The default SMTP port for outbound traffic is port 25, which is disabled by default. It cannot be enabled by security group rules. Same as the limit on basic security groups.
  • If more than 1,000 classic network-type instances need mutual access over the internal network, you can assign them to multiple security groups and authorize mutual access between these security groups.
  • If you increase the number of security groups to which an ECS instance can belong, the maximum number of rules in each security group will decrease. The product of the number of security groups to which an ECS instance belongs and the maximum number of rules in each security group cannot exceed 1,000. For example, if the number of security groups to which the ECS instance belongs is 5, 10, or 16, the corresponding maximum number of rules in each security group is 200, 100, or 60, because 5 × 200 = 1,000, 10 × 100 = 1,000, and 16 × 60 ≤ 1,000.
  • If more than 2,000 instances with private IP addresses need mutual access over the internal network, you can assign them to multiple security groups and authorize mutual access between these security groups.

Deployment set limits

Item Limit How to apply for an extension on the limit
Quota for deployment sets in each region for an account 2 Submit a ticket.
Quota for instances that can be included in a deployment set A maximum of seven instances are allowed in a zone. The number of instances allowed in a region is calculated as follows: 7 × Number of zones in the region. None.
Instance types of instances that can be created in a deployment set Instances in the following instance families can be created in deployment sets: c6, g6, r6, hfc6, hfg6, hfr6, d2, d2s, d2c, c5, d1, d1ne, g5, hfc5, hfg5, i2, i2g, i1, ic5, r5, se1ne, sn1ne, and sn2ne. For more information about instance types and their performance, see Instance families. None.

Cloud Assistant limits

Item Limit How to apply for an extension on the limit
Quota for Cloud Assistant commands that can be created in each region for an account 100 Submit a ticket.
Quota for Cloud Assistant commands that can be run by an account each day in a region 5,000 Submit a ticket.

ENI limits

Item Limit How to apply for an extension on the limit
Quota for Elastic Network Interfaces (ENIs) in each region for an account 100 Submit a ticket.

Tag limits

Item Limit How to apply for an extension on the limit
Total number of tags that can be bound to an instance 20 None

API limits

Item Limit How to apply for an extension on the limit
Quota for CreateInstance calls 200 calls per minute Submit a ticket.
Note For more information about the limits on VPCs, see Limits.