How to backup file storage NAS through VM-based backup solutions
Solution 1:
As far as I know, Veeam can handle with your task.
https://helpcenter.veeam.com/docs/backup/vsphere/direct_san_access.html?ver=95
It seems that I could do ISCSI Lun data storage, and create regular virtual disks on it, rather than having individual RDMS. This idea is very useful thus the time you'll spend on a backup will be significantly reduced.