We have an Azure VM which includes a SQL Server. There are two main drives C (server related) and F (used by the SQL Server). I've enabled daily backups of the entire VM but I notice that the backup size is only 11749 MB which is way smaller than the 470 GB used space on the F-drive. Am I right to be worried? I see in the documentation that compression and encryption is applied to backup so that the data in the vault is 30-40% smaller but that still doesn't look right!