Insufficient disk space on datastore ''.

A Virtual Machine that I just created on VSphere failed to power on, after a very long wait it failed with an Insufficient disk space on datastore ”. error.

It seemed like it was unable to create the swapfile and I could see in the Datastore that it tried to create the vswp file and it was growing bigger and bigger until it filled up the Datastore completely.

After rechecking my Virtual Machine config it was a clear what happened: I wanted to create a Virtual Machine with exactly 3,5 GB of memory so I entered 3584 but forgot to change the GB to MB!

I would expect VMWare to tell me that it’s not possible to allocate 3584 GB of memory but if you watch quickly you can see that VMWare changes the entered amount to the maximum possible (which depends on the configured blocksize) before closing the Window:

In my case this is 255 GB:


So a clear case of human error but it would have been nice if VMWare would give us a notice.