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Server Load Balancer:Limits

Last Updated:Aug 01, 2022

This topic describes the limits on Classic Load Balancer (CLB).

Basic settings

Item

Limits

Adjustable

Limits on CLB instances

You can navigate to the Quota Management page to request a quota increase. For more information, see Manage service quotas.

Maximum number of CLB instances that you can create within an Alibaba Cloud account

30

Maximum number of CLB instances that can be associated with an Elastic Compute Service (ECS) instance

50

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

200

Maximum number of listeners that can be configured for a CLB instance

50

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

40

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

3

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

1–65535

Range of frontend or backend ports that can be specified for a CLB listener (Alibaba Finance Cloud)

  • 80

  • 443

  • 2800–3300

  • 5000–10000

  • 13000–14000

Limits on certificates

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

100

Maximum number of client CA certificates that can be uploaded in a region

100

Limits on network access control lists (ACLs)

Maximum number of network ACLs that can be created in a region

50

Maximum number of IP addresses that can be added to a network ACL

300

Maximum number of IP addresses that can be added to a network ACL by making an API call

50

Maximum number of listeners that can be associated with a network ACL

50

Public key algorithms supported by CLB

  • RSA 1024

  • RSA 2048

  • RSA 4096

  • ECDSA P-256

  • ECDSA P-384

  • ECDSA P-521

N/A

Bandwidth limits

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

Pay-by-data-transfer CLB instance

Pay-by-bandwidth CLB instance

The maximum bandwidth of an Internet-facing CLB instance varies based on the region. You can view the maximum bandwidth on the instance details page in the CLB console.

The maximum bandwidth is used 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 its maximum bandwidth value.

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

The maximum bandwidth is guaranteed even when resource contention occurs. Rules on 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 peak bandwidth of all 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 peak bandwidth of all Internet-facing CLB instances in a region cannot exceed 50 Gbit/s. To request a quota increase, contact customer service.