By default, BE will install a SQL Express instance called BKUPEXEC, to hold the BEDB. The BEDB is the database which holds things like your default BE settings, jobs and job history. BE does not restrict you from using a full SQL Server instance for the BEDB. Check the SCL for your version of BE to see what SQL Server versions are supported for use with the BEDB. You can specify the non-default SQL instance during the installation process or move the BEDB after installation. See this document on how to do so.
Before you use a non-default SQL instance for the BEDB, you should read this blog to see what extra things that you need to take care of when you do so.
The non-default BEDB should also not be placed in an instance with other production databases. There will be occasions when the SQL instance needs to be restarted by BE and this would affect the other databases. The recommendation is to use a separate SQL instance for the BEDB.
Also, note that placing the BEDB on another machine exposes you to communications problems. If your LAN is congested, then BE cannot update the BEDB in a timely manner and this may result in job failures.
In addition to the cautionary notes above, you should give some thought as to how to recover the media server in case both the media server and the server holding the BEDB got wiped out. As far as I know, there is no official Symantec documentation discussing this topic. The aim of this article is to jog you into thinking about media server recovery when you are using a non-default BEDB. If you are using a default BEDB, then this article may not be of interest to you.
If you are using the BEDB, then the simplest and recommended way to recover the media server is SDR. After the SDR recovery process is complete and the media server is rebooted, you would have a fully functioning media server, ready to recover your other server.
If you are not using SDR, the manual recovery process is also simple.
a) Load the OS on the media server
b) Load BE
c) Inventory and catalog the media with the last good backup of the media server.
d) Restore the C: drive and the system state of the media server.
e) Reboot and you are good to go.
This assumes that your media server backup includes the all-important Data and Catalog directories under the BE installation directory.
Even if you recover the media server using SDR, you would not be able to bring up BE because the BEDB which is on another machine is missing. Recovering both the media server and the other server with the BEDB using SDR is still not sufficient because the BEDB is a SQL Server database and this needs to recovered separately, so you end up in a chicken-and-egg situation.
You might need to manually recover the media server and the server with the BEDB in this way
1) load OS and BE with a default BEDB on the media server
2) inventory and catalog the necessary media
3) recover the machine on which the BEDB resides
4) restore the BEDB using SQL restore or BEUTility, if this is possible
5) restore the media server to the state of last backup. Hopefully it would be able to connect to the restored BEDB on the previous step.
Before doing steps 3 and 4, it is probably necessary to restore a DC and this will complicate things for steps 3 and 4 because the media server is still not part of the AD. Step 4 cannot be avoided.
Disclaimer: I have not tested the above recovery steps because I am using a default BEDB.
The recovery process gets more complicated when the BEDB is in a full SQL Server instance on the media server. It would not be necessary to do Step 3 of the above procedure, but you would need to install the SQL Server software on the media server before doing Step 4.
I am not sure what would happen when you do Step 5 of the above procedure. The restoration will override the SQL Server software on the media server and there may be a mismatch between the timestamps of the restored BEDB and what is in the Master DB, rendering it unusable.
When you use a non-default BEDB, I would suggest that the first thing you do is to test and document the recovery steps for the media server and the server with the BEDB. Get to the point where you can recover the rest of the servers.
If there is anybody who has done this recovery, please contribute your experience to this article.