Extending Windows System Drives with vSphere

March 2, 2012 2 By Eric Shanks

vSphere has made it very simple to resize disks.  They old days of finding larger disks to put in your severs and cloning or migrating data aren’t necessary now that virtualization has become widely used.

If you’re using vSphere you can easily extend non system drives by changing the size of the Hard Disk, and then going into the virtual machine and using diskpart or Disk Manager and extending the drive.

The trick comes to older servers (pre Windows Server 2008) where you can’t extend the system drive even with diskpart.

This becomes a pretty easy task to complete because we can power off the server, detach the hard disk and attach it to another server that is running.

Go into the vm properties and remove the virtual disk from the machine.  MAKE SURE YOU DO NOT DELETE THE FILES FROM DISK

Attach that virtual disk as a second disk to another VM that is running.

Now if we go into disk manager on the new VM we can see the secondary drive still has 2 Gb of unallocated space that we want to use.

Lets try disk part again.

Now that we have successfully added the extra 2 Gb of space we can then remove the drive from the second VM and attach it to the original VM again.

Power on the server and you’ll have the extra 2Gb needed.