During the upgrade, the installer has the option to create a backup of the current database:
The Backup Location field is used to specify the full path in the SQL server(Where the database is located), e.g. C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\Backup,but you can specify any path you choose.
Note : This field is optional, however our recommendation is to create a backup of the database.