What happens when a domain controller goes down?

[udit-mishra-5113a21a]

What happens when a domain controller goes down? Assume that, it was started successfully, it read configurations from domain.xml, and "assign" them to Host controllers, and the cluster was working properly. Now it goes down suddenly, what impact it has on the cluster?

[nadirx]

The DC does not affect operations on the cluster. It can be safely restarted without interrupting availability. Obviously, during its downtime, no configuration changes can be made.

[udit-mishra-5113a21a]

Agree, and when it is up, if I make configuration changes, does it need a restart? Lets say, I have changed the number of Owners of a cache in domain.xml, do I need a restart in that case?

[nadirx]

Changes to the domain configuration should be made to the CLI instead of modifying directly the XML, if the domain is running.

You only need to restart the resource which is affected by your change: since number of owners is per-cache, you just need to restart that cache.

[udit-mishra-5113a21a]

Thanks I have asked several questions, if possible, kindly reply to this one - How to connect to a particular server group from hotrod client?

[udit-mishra-5113a21a]

Hello nadirx , I would like to have one more clarification. Lets say my cluster was running perfectly and because of some reasons, assume that the entire cluster went down. Now, upon restarting, suppose everything gets restarted, just the machine which was acting as a DC could not get restarted, so will Host controllers will be able to start and have that configuration? Will they be able to form topology? If yes, then wonderful. If no, then can I have multiple DCs just for the backup? What if both the DCs are up, will it lead to any confliction?