Recommendations for databases
Ensuring database redundancy
We recommend that you have two servers for each of the administration and log databases, and enable the Always On availability group (AG) feature in SQL Server. The functionality allows automatic or manual switching between databases in case of unavailability.
Always On functionality is not available on Express versions of SQL Server.
Managing database failure
With redundancy
If a database fails when using the Always On feature, refer to the Microsoft SQL Server documentation.
No redundancy
If you only had one administration database or logs, you must restore the machine hosting the database from a backup (virtual machine snapshot or physical machine disk image).