I am trying to add a virtual disk using a VMFS datastore with 1.98 TB of capacity and 85 GB used. I then power on the virtual machine, and it gives me the Insufficient disk space on datastore error. And so I removed the newly created disk and try to power on and it gives me the same error! I don't want to panic but I need some good advice on how to fix this and why this is happening...

Here is the configuration:

Datastore: vmfs_temp
Virtual Machine Properties - Options tab
Config file: [vmfs_temp] VM-ASSS16-INT-SQL2K8R2-1/VM-ASSS16-INT-SQL2K8R2-1.vmx
working location: [vmfs_temp] VM-ASSS16-INT-SQL2K8R2-1/
swapfile location: default

EDIT: screenshot showing disk sizes enter image description here

3 Answers 3


Take a look at all of the datastores visible to the host (in vSphere, select the host > Configuration tab > Storage). Are any of the datastores full or very close to it? The swap file may be located on a full datastore even if the VM is on another datastore and if the host cannot create the swap file, the VM will not boot.

EDIT: Right-click the VM and go to Edit Settings > Options tab > Swapfile location. Select one of the other options ("Always store with the virtual machine" is recommended and will probably work for you since that datastore has a lot of free space). As far as cleaning up that datastore, you can right-click it and Browse and poke around to see what kind of files are taking up the space. It may be likely that your host is configured to use a different datastore for all VMs by default and it is just taken up by swap files at this point.

To change the default swapfile location for the host select the host, click the Configuration tab and Virtual Machine Swapfile Location.

  • Yes!! Here I can see that the vmfs_temp datastore has 1.98 TB used and only 1.07 GB free which is probably not enough for the swap file! What can I do? Sep 9, 2011 at 17:37
  • Allright! I have left the swapfile location to Default for the Virtual Machine but I have changed the host's default swapfile location to another Datastore, and voilà! The machine starts! Thanks. Sep 9, 2011 at 18:29

How big is the virtual disk and what is the block size of the datastore? The size of the virtual disk may exceed the allowable size as predicated by the datastore block size.


  • I have added an edit to show the used space Sep 9, 2011 at 14:27
  • What I mean is that if the size of the virtual disk that you're trying to add is larger than what the block size of the host datastore supports, that might be causing the error.
    – joeqwerty
    Sep 9, 2011 at 15:12

Are there any files of the VM stored on other data stores? How full are they? Log into the host and check to see how full the other partitions of the hard drive are.

  • No, using the vSphere client, I can see that all 9 drives in total are on the same VMFS datastore Sep 8, 2011 at 19:27
  • Log into the host via ssh and check if the other partitions are full. A full log drive can cause all sorts of problems including VMs not booting.
    – mrdenny
    Sep 8, 2011 at 19:30
  • I do not follow, the host being...? you mean vSphere? With all the virtual machines? Sep 8, 2011 at 19:53
  • @JFB The drives are there, but does the .vmx live in another data store? There may not be enough space to create the swap file. Sep 8, 2011 at 20:12
  • Please see the edit above. The .vmx is on the same datastore Sep 8, 2011 at 20:24

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