Implementing HA Across Multiple AZs
CLB instances support disaster recovery across availability zones. For example, multiple clusters can be deployed in two availability zones in the same region: Guangzhou Zone 3 and Guangzhou Zone 4. This achieves disaster recovery across availability zones in the same region. With this feature, a CLB instance can forward frontend access traffic to other availability zones in the same region within 10s if the entire availability zone fails, restoring service capability.
FAQs and Use Cases
Question 1: If CLB instance test1
is configured for Guangzhou Zone 3, what is the policy for inbound public network traffic of the client?
Guangzhou Zone 3 and Guangzhou Zone 4 have a pair of IP resource pools, which can be seen as IP resources with equivalent load balancing capability. Developers do not need to figure out between the master cluster and slave cluster. When they purchase a CLB instance and bind it to CVM, two sets of rules will be generated and written into the two clusters, achieving high availability.
Question 2: Suppose that CLB instance test1
is configured for Guangzhou Zone 3 and bound to 100 real servers in each availability zone (Zone A and Zone B). During business operation, 1 million HTTP persistent connections (with TCP connections kept alive) are established in each zone. If the entire CLB cluster in Guangzhou Zone 3 fails and becomes unavailable, what will happen to the business?
When the CLB instance in Guangzhou Zone 3 fails, all current persistent connections will be closed, while non-persistent connections will not be affected. The disaster recovery architecture will automatically bind the 100 servers in each zone to the CLB instance in Guangzhou Zone 4 within 10s, immediately restoring business capability with no manual intervention required.
Question 3: Which type of CLB is compatible with multi-AZ disaster recovery? Does it cost extra fees?
The multi-AZ disaster recovery is in beta test, and no extra fees will be charged. Currently, only public network CLB supports multi-AZ disaster recovery. Different from the cross-AZ disaster recovery of public network CLB, private network CLB supports nearby access by default.
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