Hello Guy,
When adding connection profile in DMC, there has an option for initializing HADR, that will detect all the HADR standbys information base on the primary node's information. The detected host info of the standbys may be an internal IP. With the internal IP, DMC can not establish connections to standby databases so that DMC can not monitor them.
So if you want to monitor your databases as a HADR group. we suggest to assign a public IP to each HADR member. In the HADR initiate process, we can replace the internal IP to public IP, so that DMC can communicate to the standby database.
If you don't need to monitor the whole HADR group, I think that's OK to use only one VIP to connect and monitor the only one HADR database.
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Tao Wen
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