Recently, I have done a nice project: Implementing VMware Stretched Cluster. One of the pre-starting activity was migration VMs vmdk between datastores by Storage vMotion. It was done by my customer but they informed me that Storage vMotion powered off some VMs! I was not able to believe so I checked it on-site and it was the truth...
After some investigation, I found out that it is bug here:
PR1118780: Storage vMotion of Powered On VMs with Raw Device Mapping (RDM) disks might fail and result in the VM to Power Off. Attempts to Power On the source virtual machine might fail with an error message similar to the following:
Failed to lock the file.
The problem is that customer didn't migrate VMs with RDM and also the VMs were able to be powered on without above error. So symptoms were not exactly the same as above bug. Despite it, the first thing which I did - patching the vSphere infrastructure (customer never updated their ESXi 5.5 hosts...) has solved the problem.
So, always patch your vSphere environment! 🙂