Quota limits for Alibaba Cloud Classic Load Balancer (CLB)-Server Load Balancer(SLB)-阿里云帮助中心

This topic describes the quotas and bandwidth limits for Classic Load Balancer (CLB) and explains how to request an increase.

Quotas

CLB instance limits

Resource	Default quota	Adjustable
Number of CLB instances per Alibaba Cloud account	60	You can request a quota increase in one of the following ways: Go to the Quota Management page to increase the `slb_quota_instances_num` quota. For more information, see Manage quotas. Go to Quota Center to increase the quota. For more information, see Manage CLB quotas.
Number of CLB instances to which a backend server can be added	50	You can request a quota increase in one of the following ways: Go to the Quota Management page to increase the `slb_quota_backendserver_attached_num` quota. For more information, see Manage quotas. Go to Quota Center to increase the quota. For more information, see Manage CLB quotas.
Number of backend servers per CLB instance	200	You can request a quota increase in one of the following ways: Go to the Quota Management page to increase the `slb_quota_backendservers_num` quota. For more information, see Manage quotas. Go to Quota Center to increase the quota. For more information, see Manage CLB quotas.
Number of listeners per CLB instance	50	You can request a quota increase in one of the following ways: Go to the Quota Management page to increase the `slb_quota_listeners_num` quota. For more information, see Manage quotas. Go to Quota Center to increase the quota. For more information, see Manage CLB quotas.
Number of domain name-based and URL-based forwarding rules per HTTP or HTTPS listener	40	Not adjustable
Number of additional domain names per HTTPS listener The default is 3. You can request an increase up to 10.	3	You can request a quota increase in one of the following ways: Go to the Quota Management page to increase the `slb_quota_domain_extensions_num` quota. For more information, see Manage quotas. Go to Quota Center to increase the quota. For more information, see Manage CLB quotas.
Frontend and backend port range for a listener (public cloud)	1 to 65535	Not adjustable
Frontend and backend port range for listeners on Internet-facing CLB instances (Financial Cloud)	80 443 2800 to 3300 5000 to 10000 13000 to 14000 21234 22223 22225 The following ports are not supported: 2967, 2989, 3024, 3074, 3127, 3128, 3129, 3132, 3150, 3198, 3210, 3268, 3269, 5000, 5001, 5002, 5011, 5025, 5031, 5032, 5190, 5321, 5333, 5343, 5400, 5401, 5402, 5471, 5512, 5521, 5550, 5554, 5555, 5556, 5557, 5569, 5598, 5631, 5632, 5637, 5638, 5678, 5679, 5698, 5714, 5720, 5741, 5742, 5760, 5880, 5881, 5882, 5888, 5889, 5900, 6000, 6006, 6073, 6129, 6272, 6267, 6400, 6500, 6661, 6666, 6667, 6668, 6669, 6670, 6671, 6711, 6712, 6713, 6723, 6767, 6771, 6776, 6777, 6789, 6838, 6883, 6912, 6939, 6969, 6970, 7000, 7001, 7201, 7215, 7300, 7301, 7306, 7307, 7308, 7323, 7424, 7511, 7597, 7609, 7626, 7777, 7789, 7983, 8000, 8010, 8011, 8102, 8181, 8520, 8594, 8787, 8897, 8989, 9000, 9080, 9325, 9400, 9401, 9402, 9535, 9872, 9873, 9874, 9875, 9876, 9878, 9989, 9898, 9999, 13000, 13010, 13013, 13223, and 13700. For more information, see Financial Cloud product limits.	Not adjustable

Certificate limits

Resource

Default quota

Adjustable

Number of server certificates that you can upload per region

100

You can request a quota increase in one of the following ways:

Go to the Quota Management page to increase the slb_quota_certs_num quota. For more information, see Manage quotas.
Go to Quota Center to increase the quota. For more information, see Manage CLB quotas.

Number of client CA certificates that you can upload per region

100

You can request a quota increase in one of the following ways:

Go to the Quota Management page to increase the slb_quota_ca_certs_num quota. For more information, see Manage quotas.
Go to Quota Center to increase the quota. For more information, see Manage CLB quotas.

Access control list (ACL) limits

Resource	Default quota	Adjustable
Number of access control lists (ACLs) per Alibaba Cloud account	200	Not adjustable
Number of entries per ACL	300	You can request a quota increase in one of the following ways: Go to the Quota Management page to increase the `slb_quota_acl_entries_num` quota. For more information, see Manage quotas. Go to Quota Center to increase the quota. For more information, see Manage CLB quotas.
Number of IP addresses or CIDR blocks you can add to an ACL in a single API call	50	Not adjustable
Number of listeners an ACL can be associated with	50	You can request a quota increase in one of the following ways: Go to the Quota Management page to increase the `slb_quota_acl_attached_num` quota. For more information, see Manage quotas. Go to Quota Center to increase the quota. For more information, see Manage CLB quotas.
Public key algorithms supported by CLB	RSA 1024 RSA 2048 RSA 4096	Not adjustable

Bandwidth limits

CLB uses a distributed and highly available architecture. If the number of clients is too small, the CLB instance may not reach its bandwidth limit. To perform a stress test at full speed, you need at least five clients.

The following table describes the bandwidth limits for Internet-facing CLB instances that use different billing methods.

Pay-by-data-transfer

Pay-by-bandwidth

The maximum bandwidth for a pay-by-data-transfer, Internet-facing CLB instance varies by region. The actual value is displayed on the Instance Details tab in the console.

This bandwidth cap is for reference only. During resource contention, the actual bandwidth may be lower.

The maximum purchasable bandwidth for a pay-by-bandwidth, Internet-facing CLB instance varies by region. For more information, see the instance buy page.

The bandwidth cap is a guaranteed performance metric, even during resource contention. The following rules apply to inbound and outbound traffic:

Inbound bandwidth: Alibaba Cloud allocates inbound bandwidth equal to the purchased maximum bandwidth.
Outbound bandwidth: Alibaba Cloud allocates outbound bandwidth equal to the purchased maximum bandwidth.

Within a single region, the total bandwidth of all pay-by-data-transfer, Internet-facing CLB instances under an Alibaba Cloud account cannot exceed 5 Gbps. If your service requires a guaranteed or higher bandwidth, use pay-by-bandwidth CLB instances.

Within a single region, the total bandwidth of all pay-by-bandwidth, Internet-facing CLB instances under an Alibaba Cloud account cannot exceed 50 Gbps. To request a higher limit, contact your account manager.

Log on to the CLB console. On the Instances page, click the ID of the desired instance. On the Instance Details tab, view the Bandwidth value.
To understand why a CLB instance may not reach its bandwidth or QPS limits in some scenarios, see Why do connections fail to reach the maximum bandwidth in specific scenarios? and Why does a CLB instance fail to reach the maximum QPS in specific scenarios?.