You could setup a replica job, only the disks you want. To use on other VM vmfs file just remap the replica disks to the VM using for testing. It the data on the disks will change during your testing then snapshot the replica first, map disks, do tests, unmap disk from other VM, delete snapshot. Only change blocks of the disks will need to be copied each night. You can also copy the vmfs file to other VMs if needed but would do the whole 5tb each night. I have use this when a server died during a patch wiping the c: drive. I then just copied the C: drive from backup to production leaving all the data disks in place, server reboots like nothing has happened all data saved.