Over Provisioned VMWare 6.0 VM Storage, VM Won't Start?

Question

I recently updated a free licensed VMWare ESXi host to 6.0 (I do not have access to vcenter). The host has 6 datastores available, the first two of which reside on SSD's and are fairly small (I typically use those for my VM OS, and any VM's that need more storage can use one of the mechanical datastores). The upgrade went fine and all my machines started.

I decided to shut down one of the machines and expand it's OS storage. My datastore1 has a but more than 70GB free, so I extended the VM's guest disk size from 160GB to 229GB figuring I'd still have some wiggle room there. I guess that was my first mistake. I was unaware that apparently you can easily increase a virtual disk size, but decreasing it is not possible. Now my VM won't start!

Failed to start the virtual machine.
Failed to power on VM.
Could not power on virtual machine: msg.vmk.status.VMK_NO_SPACE.
Current swap file size is 0 KB.
Failed to extend swap file from 0 KB to 16777216 KB.

Now I've tried multiple things, starting from removing snapshots etc. to try to free up some space, to migrating the virtual disk to another datastore and then using vcenter converter to move it back but to a smaller disk (that failed horribly, took several hours and when all was said and done, the VM could only PXE boot, said no operating system found).

I still have a few copies of the virtual disk but they're all 230GB virtual disks. If I change the VM settings to run the virtual disk off of one of the larger mechanical datastores, it does still work fine (OS boots etc.) but I really want to get this thing back down to 160GB and moved back to my SSD datastores.

Now, I have NOT utilized the extra space provisioned to this VM. fdisk still shows 160GB drive / partitions, so I have not even touched the extra provisioned space yet. I am not trying to reduce the partition, I want to reduce the space provisioned to this VM and ultimately the VMDK file so I can move it back to my SSD datastore and fire it up again.

I have searched all over but I feel I may be using the wrong terminology as many of my results seem to end in "it's not possible without data loss" but I feel since I haven't used the extra provisioned space it simply has to be possible. Maybe I'm wrong. Can anyone help point me in the right direction?

Thanks in advanced for any replies!

YSK YSK · Accepted Answer · 2017-05-30T03:38:58

I don't know of a documented way to shrink a disk without VMware Converter, but VMware Converter should work. Have you verified you gave all the correct arguments (most notably the new size)? You can try mounting the resulting VMDK on a different VM (as a data disk) to see if there's anything wrong with it.

Have you considered making the disk thin-provisioned? See this VMware KB for how to achieve this without vCenter (you'll need to ssh into the ESXi). Since the last 69GB of the disk are zeros, it can help you reclaim that space.

If all else fails and you're feeling adventerous, you might be able to manually edit the VMDK file and prune the last part of it.

Over Provisioned VMWare 6.0 VM Storage, VM Won't Start?

1 Answers