GSLB] Web,Was,DB server Pools LB

Customers are operating Web, Was, and DB servers in 3 centers.

When the client queries the Web Domain, the server queries Was and the DB server as the domain and processes the data.

The current topology policy is that if the client network is in the region

The policy is set to prioritize the pools of the center to which the client belongs.

1 center: Topology applied in the order of 1 center> 2 center> 3 center

Center 2: Apply topology in the order of Center 2> Center 1> Center 3

Center 3: Apply topology in the order of Center 3> Center 2> Center 1

One problem arises here.

When a user queries the web server in Center 1, Was DB also performs LB to the server in Center 1.

Here, if the web dies based on center 1, the query is made to the web server of the 2 center and the was, DB server of the center 2 is used.

So far, it's going well.

The problem is when either DB or Was dies.

Assuming that the DB is dead

For 1 center, the web is queried at 1 center, the DB is 2 centers (different network bands), and Was 1 center.

This will cause problems in service operation.

How can I switch to another center even if only one of Web, Was, and DB dies?