We migrated a Virtual Machine with 2 disks attached to it:

1. 53GiB root disk
2. 150GiB data disk

At the end of the transfer, the VM in Openshift showed the drives:

1. 58Gib root disk
2. 165Gib data disk

The expectation is the drive sizes remain the same.  If it matters, both drives are configured as xfs filesystems in the VM.

Another issue related to the FS overhead: https://github.com/kubev2v/forklift/issues/397