I'm using ESXi 6.0.0, and come up with a question. How does ViClient/ESXi know if a thick vmdk is lazy zeroed or eager zeroed? I checked the .vmdk content(several hundred bytes) from command-line shell and cannot identify a field that describes such difference.
I think the flag is not related to the disk image itself, rather it is a VM property.
After all, for the filesystem both files (lazy & eager zeroed) are absolutely the same; on the other hand, for the VM (and the disk management console) the two files should be treated differently.