Diskpart is a newer utility from Microsoft that replaces the ancient Fdisk for creating and manipulating hard drive partitions. It's biggest strength is that it is free and that it brings more powerful / modern tools to the Windows world for disk partitioning.
As anyone that uses VMWare ESX knows it is really easy to add space to existing Virtual Hard Drives. The difficult thing is utilizing the extra space in the Windows Server. The problem is compounded when using Templates in VMWare to deploy a server. You want the template to take up as little space as possible when in storage but need to expand that partition to an appropriate size in production. Window's native gui utility Disk Management doesn't have the ability to "Expand" disk partitions (Windows Server 2003). Diskpart though allows you to do that rather easily albeit with a few exceptions but I'll show you how to get around those exceptions as well.
As usual all of these steps have been tested successfully in my Test Lab. I am not responsible for any problems that you may encounter. I would also recommend that you only do this on a new Server Template deployment and not a live production system. If you must do this to a live server make sure you "Clone" your server before you begin so you have a backup you can recover from should something go wrong. That being said, if you follow these steps closely you should have no problems.
First Deploy your server within VMWare's VCenter. Once it's established go in to "Edit Settings" of the Virtual Machine.
After clicking "Edit Settings" you will see the properties for the Virtual Machine as below:
Highlight Hard Disk 1 and under "Disk Provisioning" increase the provisioned size to whatever you need for production. In this case we'll increase it to 150GB.
As you can see above the Size has been increased to 150GB. All of this can be done while the Windows Server is on. Hopefully you noticed in the screenshots above there is only 1 Virtual Hard Disk installed in this server. It must therefore be the C: partition of Windows. As I said above there is a catch with DiskPart and the Boot Volume in Windows Server 2003. You cannot "Expand" the partition on the Boot Volume, sort of. It is more precise to say that you cannot "Expand" the Boot Volume while it is Active. The way around this is to attach the Virtual Hard Disk as a second Volume on another server. In this way the Disk you want to "Expand" is not Active.
The first thing you need to do is "Shutdown" the server that you want to expand the partition on. Once it's turned off go to the "Edit Settings" of another Virtual Machine that is active.
As highlighted above Click on the "Add" button.
Highlight "Hard Disk" and select the "Next" button.
Choose to "Use an Existing Virtual Disk" as shown above and click on "Next".
We now need to browse to the Virtual Hard Disk File that we want to Expand. Be careful here, you want to make sure that you select the correct disk file for the correct server.
After Clicking the "Browse" button you'll be taken to a listing of your DataStores. Select the DataStore that contains the Virtual Machine with the Hard Drive that you want to expand.
Find the folder containing the files for your Virtual Machine that you want to expand. Select the Hard Drive file and click Ok. The file will have a .vmdk extension.
Once selected VMWare will give the hard drive the next Available Virtual Device Node. Nothing further needs to be done with this screen. Click Next.
The final summary screen will be shown as above. Click Finish to complete adding the Virtual Hard Disk to the server.
This attaches our 150GB Virtual Hard Drive to the live Windows Server. We now need to go into Windows by opening a Console session to the Server. Once on the Windows 2003 server Open the Computer Management Interface and Highlight Disk Management.
With Disk Management Highlighted you should see all of the Virtual Hard Drives attached. If you don't see the second Hard Drive right away, Right Click Disk Management in the Left Window and Select "Rescan..." from the popup menu. This should make the second Hard Drive appear in the Window as shown above. You can see the Boot Volume of this server above shown as Disk 0. The Disk we want to expand is shown as Disk 1. You can also see that the 1st partition on that drive is the original 128GB and there is an additional space after that shown as "Unallocated". That is the additional space that we added through VMWare.
Now we need to open a Command Prompt in Windows. At the command line type "diskpart" and press enter.
Next type "list volume" to see the listing of Hard Disks that are detected by "DiskPart". You can easily identify below the difference between the Boot Volume and Expansion Volume by examining the Sizes.
Next type "select volume 1" and press enter.
Now type "extend" at the command line and hit enter.
As you can see above the expansion of the existing partition was successful. You can also see the confirmation of the new size in Disk Management. It now shows 150GB for the full size. Finally type "exit" to close out DiskPart.
Now we need to clean things up. Go back in to "Edit Settings" of the current Virtual Machine. We need to remove the second drive that we expanded from this machine.
Highlight the second drive, in this case Hard Disk 2 and click the "Remove" button. Make sure that you also select "Remove from virtual machine". We don't want to remove and delete the files, we still need those for the original Virtual Machine. Click Ok to remove the drive.
Since we didn't remove this drive from the original Virtual Machine it is ready to go. Power on the Virtual Machine and log into Windows when ready. You will get the following prompt. Click "Yes" to reboot and finalize the detected changes.
After rebooting log back in and open Computer Management, then highlight Disk Management.
You'll now see that your boot volume C: has been expanded to 150GB and works just fine. If you need to expand a secondary drive attached to the same server it's even easier. Just do the DiskPart instructions again. Make sure to apply all the steps to the drive you want to expand. There is no need to attach the drive to another host virtual machine since it isn't the boot volume. In Windows Server 2008 it gets even easier. Back another time with much briefer instructions on that.
As always I hope you found this useful. If you did let me know, leave a comment.