An administrator is attempting to power on a virtual machine with 32GB of memory. The operation fails with the following error:
-Could not power on VM : No space left on device
-Checking the space on the virtual machine’s datastore, there is 30GB free.
Which action would allow the VM to power on?
A. Set a 2GB memory reservation on the VM.
B. Mount the virtual disk from the affected VM on to another virtual machine and free up space from within the OS.
C. Enable vSphere HD admission control on the cluster in which the VM resides.
D. Set a 2GB memory limit on the VM.
I found it confusing a bit, so i searched.
I think this answer covers the situation quite well and it would explain why answer A would be correct :
By default, ESXi creates a swap file with the size of the VM’s configured memory. Since this seems to be a stand-alone host, and there’s no memory overcommitment (as far as I understand it), you may change the VM’s settings and set/increase the “Memory Reservation”. The swap file size will then be “assigned memory” minus “reservation”, i.e. if you set the reservation to 128GB, the swap file size on the datastore will be zero.
André
Link : https://communities.vmware.com/thread/579531