Help Center/ Distributed Cache Service/ Drawer/ Buying a DCS Instance/ AZ
Updated on 2025-07-24 GMT+08:00
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AZ

Parameter Explanation

  • AZ

    An AZ is a physical region where resources use independent power supplies and networks. AZs are physically isolated but interconnected through an internal network.

    Each region contains multiple AZs. If one AZ is unavailable, the other AZs in the same region continue to provide services.

  • Primary AZ

    AZ where the master node is located.

  • Standby AZ

    AZ where the standby node is located.

FAQs

How Do I Select an AZ?

For a master/standby, read/write splitting, or cluster instance, deploy the master and standby nodes in different AZs (in different equipment rooms).

When a fault occurs in the AZ where the master node is deployed, the standby node connects to the client and takes over data read and write operations. For details, see Cross-AZ DR Within a Region.

Cross-AZ deployment does not compromise the speed of data synchronization between the master and standby nodes.

Can I Change the AZ for an Instance?

By enabling multi-AZ for a single-AZ cluster instance, you can deploy the instance in two AZs for DR. For details, see Changing Cluster DCS Instances to be Across AZs.

The AZ of a created instance cannot be changed. To use a different AZ, create another instance in the desired AZ and then migrate data. For details, see Online Migration Between Instances.

Parent Topic: Buying a DCS Instance