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Server Load Balancer:Limits

Last Updated:Dec 01, 2023

This topic describes the limits on Classic Load Balancer (CLB), including resource quotas and bandwidth limits. This topic also describes how to request a quota increase.

Resource quotas

Limits on CLB instances

Item

Default value

Adjustable

Maximum number of CLB instances that can be created by each Alibaba Cloud account

30

You can request a quota increase by using one of the following methods:

Maximum number of times that a server can be added as a CLB backend server

50

No

Maximum number of backend servers that can be added to a CLB instance

200

You can request a quota increase by using one of the following methods:

Maximum number of listeners that can be added to a CLB instance

50

You can request a quota increase by using one of the following methods:

Maximum number of domain name-based and URL-based forwarding rules that can be added to an HTTP or HTTPS listener

40

No

Maximum number of additional domain names that can be created for an HTTPS listener

The default quota is 3. The highest quota that you can apply for is 10.

3

You can request a quota increase by using one of the following methods:

Range of frontend or backend ports that can be specified for a CLB listener (public cloud)

1~65535

No

Limits on certificates

Item

Default value

Adjustable

Maximum number of server certificates that can be uploaded in a region

100

You can request a quota increase by using one of the following methods:

Maximum number of client certificate authority (CA) certificates that can be uploaded in a region

100

You can request a quota increase by using one of the following methods:

Limits on ACLs

Item

Default value

Adjustable

Maximum number of access control lists (ACLs) that can be configured by an Alibaba Cloud account

200

No

Maximum number of entries that can be added to an ACL

300

You can request a quota increase by using one of the following methods:

Maximum number of IP addresses or CIDR blocks that can be added to an ACL in each API call

50

No

Maximum number of times that each ACL can be associated with different listeners

50

You can request a quota increase by using one of the following methods:

Public key algorithms supported by CLB

  • RSA 1024

  • RSA 2048

  • RSA 4096

  • ECDSA P-256

  • ECDSA P-384

  • ECDSA P-521

No

Bandwidth limits

The following table describes the maximum bandwidth of Internet-facing CLB instances that use different metering methods for Internet data transfer.

Pay-by-data-transfer CLB instance

Pay-by-bandwidth CLB instance

The maximum bandwidth of a pay-by-data-transfer Internet-facing CLB instance varies based on the region. You can view the maximum bandwidth of a pay-by-data-transfer CLB instance on the instance details page in the CLB console.

The maximum bandwidth is for reference only. It indicates the upper limit of the bandwidth. In case of resource contention, the bandwidth allocated to each CLB instance may be lower than the maximum bandwidth value.

The maximum bandwidth that you can specify for a pay-by-bandwidth Internet-facing CLB instance varies based on the region. For more information, visit the buy page.

The maximum bandwidth is guaranteed even if resource contention occurs. Rules for inbound and outbound bandwidth:

  • Inbound bandwidth of a CLB instance: the maximum bandwidth that you specify when you purchase a CLB instance.

  • Outbound bandwidth of a CLB instance: the maximum bandwidth that you specify when you purchase a CLB instance.

For each Alibaba Cloud account, the sum of the maximum bandwidth of all pay-by-data-transfer Internet-facing CLB instances in a region cannot exceed 5 Gbit/s. If your business requires guaranteed bandwidth or larger bandwidth, you can purchase pay-by-bandwidth CLB instances.

For each Alibaba Cloud account, the sum of the maximum bandwidth of all pay-by-bandwidth Internet-facing CLB instances in a region cannot exceed 50 Gbit/s. To request a quota increase, contact your account manager.