In the case of a relational database server failure, ESRI recommends that we restore geodatabases from backups on new server, make all new connection strings to new database Instance (machine name), fix every database connection error in every map and/or ArcGIS Pro project that is connected to an Enterprise database (SQLServer/Oracle, etc.), republish every service on your Enterprise ArcGIS Servers and potentially check/fix all maps and their popups. This process, to me, sounds like potentially a ton of work to get your Enterprise back up and running again.
I proposed that there is, potentially, another solution that cuts the work down to a few hours at best. Our servers are virtual on VMware. This approach still would work with stand alone physical machines used as database servers as well.
I could not get confirmation form Tech support that this approach works as they have apparently never had anyone with a failing DB Server to confirm this method, so I thought I would ask the Community if this seems to be a way around this type of disaster recovery without all of the work.
Please let me know if anyone else has had a failing DB Server and tried another method.
We recently had a scenario where a database server failed. We had to spin up a new server VM with the same name and restore all of the databases from a backup onto that VM. Since the VM server name stayed the same, we didn't have to change any of the connections within Esri. I'm not sure if that answers your questions, but that is the situation we experienced when our server crashed.
I'm not a DBA, so I'm not exactly sure what all extra had to be done. I do know that the user account used to publish feature services to server did not have permission to access the databases, so that had to be fixed. But I'm not sure about the details. I just know that I didn't have to update any connections or anything like that within Esri.