OK, Database Server 5 is back online. I am still looking into it and will update here later.

Massive SNAFU! I can't apologise enough but it was not on my end.

The old drive stored the EFI and that is required to boot the server. The person that did the disk replacement didn't know that (EFI cannot be on the RAID), so they were hours attempting to reboot the server without EFI, until they gave up and handed me the broken server.

Now, an attempt will be made to place the old drive back and see if the server boots like that and then I can fix the situation.

There is a problem with the disk replacement that is causing the server not to boot. They are trying to understand what could be causing the problem.

I am really sorry but it's something that I have no access to and will have to rely on the information I am provided, causing me to provide timings and have expectations that are inaccurate.

I'm contacting everyone I can to obtain more informations and ways to speed up the process.