VM Backup

[Saif Ahmad]

I have 1 VMrunning in Azure. I added 3TB standard disk storage to that server and created a secondary disk to upload all of my data. This server is acting as a file server. I setup backup vault and the sever is taking daily/nightly snapshots, but want i want to know is how is this data backed up? Is the VM backed up entirely including the 3TB standard storage that i have attached to it or not? 

[#2]

Its incremental though not state in clear print, statement below implies that 

As the amount of data in the virtual machine grows, the Protected Instance size used for billing changes accordingly.

........the size of the last successful VM backup becomes the Protected Instance size used for the monthly bill.

https://docs.microsoft.com/en-us/azure/backup/backup-azure-vms-introduction#calculating-the-cost-of-...