Limits

Last Updated: Sep 25, 2017

Unless otherwise specified, all the resource limits listed in the table are for one region.

Restricted item Parameter To apply for an exception or unlock configuration rights
User creation of ECS resources N/A Users must undergo real-name authentication
Zones in which users may create instances 1 online zone Request increase via ticket
Zones in which users may create disks The zone combinations in which users may create instances and the zones where instances will remain after overlap removal N/A
Default Pay-As-You-Go instance types ecs.t1.small (single-core 1 GB) Request change via ticket
ecs.s1.small (single-core 2 GB)
ecs.s1.medium (single-core 4 GB)
ecs.s2.small (dual-core 2 GB)
ecs.s2.large (dual-core 4 GB)
ecs.s2.xlarge (dual-core 8 GB)
ecs.s3.medium (quad-core 4 GB)
ecs.s3.large (quad-core 8 GB)
ecs.m1.medium (quad-core 16 GB)
Default Pay-As-You-Go instance quota in all regions 30 Request increase via ticket
Disk quota within a single instance 17, including one system disk and 16 data disks No higher configurations exist
Support for Pay-As-You-Go ephemeral disks Supported For APIs, open a ticket. Other types do not support this disk type
Capacity of a single ephemeral disk 20 to 1,024 GB No higher configurations exist
Total ephemeral disk size for a single instance 2,048 GB No higher configurations exist
Number of snapshots (Number of disks)*64 No higher configurations exist
Capacity of a single basic cloud disk 5 to 2,000 GB No higher configurations exist
Number of accounts to share a single custom image with 50 No higher configurations exist
List of available public images List of images for sale on the official website Common users cannot change; for others, open a ticket to add other images
Available inbound bandwidth for Internet access Up to 200 Mbps No higher configurations exist
Available outbound bandwidth for Internet access Up to 200 Mbps No higher configurations exist
Number of instances allowed in a single security group 1,000 No higher configurations exist
Number of authorization rules for a single security group 100 No higher configurations exist
Security group quota 100 Request increase via ticket
Maximum number of security groups that a single instance can belong to 5 No higher configurations exist
Restrictions on image and instance types Instances with 4 GB or more of memory cannot use 32-bit images N/A
Adding new disks for ephemeral disk instances Not supported N/A
Changing the configuration of an instance with ephemeral disks Bandwidth is adjustable No exceptions (cloud disks can be used for attachment)
Relationship between the system disk and data disk If the system disk is a cloud disk, all data disks must be cloud disks N/A
Total number of Pay-As-You-Go cloud disks that can be purchased ECS Instance Quota * 5 Open a ticket
Basic cloud disk capacity 5 to 2,000 GB No higher configurations exist
User restrictions for the creation of Pay-As-You-Go cloud disks Users must pass real-name authentication (for buy only) N/A
Range of system disk attaching points /dev/xvda N/A
Range of data disk attaching points /dev/xvd[b-z] N/A
Capacity of a single SSD Cloud Disk 20 to 2,048 GB No higher configurations exist
Capacity of a single ultra Cloud Disk 20 to 2,048 GB No higher configurations exist

Besides all listed in the preceding table, neither does ECS support:

  • Sound card applications.
  • The installation of external hardware devices such as hardware dongles, USB drives, external hard drives, and the USB security keys issued by banks.
  • SNAT and other IP packet address translation services. Achieve this using an external VPN or proxy.
  • Multicast protocol. If multicasting services are required, unicast point-to-point method is recommended.
  • Virtual application installation or subsequent virtualization such as when using VMware.

For limitations of VPC, see Limitations in VPC Product Introduction for details.

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