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.