Our backup application invokes VixDiskLib_PrepareForAccess() as VMware doc suggested to wait for vMotion to finish (please refer to page 38 in vddk55_programming.pdf), but seems the API does not work.
We have done the followings to verify its behavior –
1. When vMotion is in progress, call the API.
Expected: The API should fail to indicate vMotion is in progress.
Actual: The API succeeded
2. The VMware API VixDiskLib_PrepareForAccess()and VixDiskLib_EndAccess() can disable and enable “Migrate…” effectively on GUI respectively as in below screenshots.
From the above, we think VixDiskLib_PrepareForAccess() and vMotion cannot block each other pragmatically, the API can only disable manual migration initiated from GUI. Can you please explain the behavior of the API?
ESX version: 
vCenterversion: 
VDDK version: 