Howto: Expand your C:\ drive in VMWARE ESX 3.5

Just as I did some days ago, you may face the problem that you’re running out of diskpace on your C:\ drive (system drive)  in VMWARE. Expanding the system drive is not as easy as expanding a non-system drive (like D:\, E:\ or whatever partitions you may have in your server :) )

These steps will guide you to expand your C:\ drive easily and without any risk. To ensure you don’t lose any data, we first have to make a backup of the vmdk. To do this, turn off the virtual machine a make a copy of the vmdk of the target server. You can do this with WinSCP for example, but if you don’t know how to use that, you can also make a clone of the server. A clone is a good backup too :)

Now that we have backup, we can start with the necessary steps to expand the disk. The following steps are taken from a forum topic of VMWARE. All credits go to GordonG.

1.3.0 Use the VI Client to connect to VirtualCenter

1.3.1 Remove the Disk from the Original Server

• Select the VM, right-click and select Edit Settings
• Select the hard disk and select Remove (DO NOT select the option to Remove and Delete).
• Click OK to apply the changes.

1.3.2 Add the Disk to the Temporary Server

• Select the VM, right-click and select Edit Settings
• Click Add, then Hard Disk, Use An Existing Disk.
• Browse to the datastore, directory and select the vmdk file that we are working with.
• Click OK to apply the changes.

1.3.3 Expand the Partition

• If the temporary server was shutdown boot it. If it was running, logon, go to Disk Management and do a rescan to detect the new disk.
• Note that this will only work with Windows 2003 SP1 or later and only when the partition is the only one on the disk.
• Login to the server as an administrator
• Open a Command Prompt (*cmd*)
• Type Diskpart
  Type list volume
  Type select volume n (where n is the volume/ partition you want to extend. Check the drive letters and use Disk Management to be sure).
  Type extend
  This will extend the selected volume to fill the entire disk. Check the changes in Disk Management

1.3.4 Remove the Disk from the Temporary Server

• Shutdown the Temporary Server.
• Select the VM, right-click and select Edit Settings
• Select the hard disk and select Remove (DO NOT select the option to Remove and Delete).
• Click OK to apply the changes.

1.3.5 Add the Disk Back to the Original Server

• Select the VM, right-click and select Edit Settings
• Click Add, then Hard Disk, Use An Existing Disk.
• Browse to the datastore, directory and select the vmdk file that we are working with.
• Click OK to apply the changes.
• Power on the VM and check the disk in Disk Management.