What does a snapshot of independent disks take?

Hi,

I am trying to figure out what can be captured in a snapshot if all my disks are independent persistent disks.

I have a machine with 3 disks, they are all marked as independent and persistent. I know the snapshot was taken after the disks were marked as independent because you can't change the mode of a disk after it already has a snapshot. Hence my question, what would be captured in a snapshot if all the disks are marked as independent and persistent.