Google Cloud Platform introduced online resizing of Google Cloud Persistent Disks almost a month ago. When I first read about this feature, I was so amazed that I had to try it right away.
I started with a Compute Engine instance with a persistent disk of size 100GB and doubled it to 200GB with a few clicks and resize2fs command.
Not only it worked flawlessly but it was also very quick. I documented my experience in this Cloud Minute video.