I am working on a “top secret” upcoming product (around Cloud of course) and because of that I am testing various things. I had never noticed this before but today I wanted to change the size of a disk within vCenter as part of the test procedure. For some weird reason this option was greyed out:
I checked if there was a snapshot on the disk but that wasn’t the case. I tried the same thing on a different VM and it actually wasn’t greyed out. Then I noticed the difference between the VMs… The VM on which it was greyed out had an “IDE” disk and the other VM had a “SCSI” disk. It appears that it is currently not possible to change the size of an IDE virtual harddisk within vCenter.