1. The licensing is 'per server' that you want to virtually restore the DB to. So in your instance if you intend to mount the backup files on the DRP SQL Server only as virtualy restored databases then you only need one license. If you want to virtually restore on any of the other servers then you need a license for those servers too. Much like the licensing for SQL Backup.
2. The server does not need a license of SQL Backup installed. SQL VR will uncompress the .SQB on the fly.
3. SQL Virtual restore is not part of SQL Backup, it is its own seperate tool. We have a great value bundle called the SQL Backup and Restore Bundle that contains both backup tools and SQL Virtual Restore. This is a valid upgrade path for you.
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