Basically, treat it as a backup & recovery.
I still find it hard to find the links in Google, so here are some direct links:
Backup
https://help.hcltechsw.com/bigfix/10.0/platform/Platform/Installation/c_backup_procedure_windows.html
Restore:
https://help.hcltechsw.com/bigfix/10.0/platform/Platform/Installation/c_recovery_procedure.html
Test:
https://help.hcltechsw.com/bigfix/10.0/platform/Platform/Installation/c_verification_of_restoration.html
If your database is local on the root server, just go through the whole procedure. You can dry-run with the old server online, but for the final migration it is cleaner to shut down the old root server’s services before taking the final SQL and File backups.
If your database is remote, take the SQL backups but no need to restore them unless you encounter a problem and need to recover. Perform a clean installation on the new server, specifying to install with a remote database and point it to your database server & instance - the database won’t be erased, but the new server won’t have the correct site files yet. After the installation, stop the new server’s services and restore or copy the files specified in the Backup link to the new server.
Bring the new server online again, check that it is responding correctly from a local console connection, then set up a DNS Alias to point the original masthead name to the new server (by new name or IP address) so the clients and relays will connect to the new server.
If you want a little more guidance you can write out your migration plan and open a support ticket for our support folk to look over it, and ensure we have someone ready at your migration time in case any issues come up. Particularly on large or complex deployments it can be a real timesaver to have an open ticket ahead of time so we don’t lose any time getting the background information. Server upgrades and migrations are something our Services team would be happy to help with, if you need some extra assistance DM me and I an get you in touch with the right contacts.
Edit: in both cases when installing the new server, choose the option to “install with existing masthead file”, and reference the masthead.afxm or actionsite.afxm, along with your license.crt and license.pvk from the original server