When running virtual Windows 2003 systems (e.g. in VMware), it's sometimes necessary to increase the size of the disks to add more storage to your machine. Starting from Windows 2008, you can perform an online increase of NTFS partitions using Storage Manager. In Windows 2003, it's also possible to perform an online extend by using diskpart from the command line.

Extending an NTFS volume

First, make sure to extend the physical volume (e.g. by increasing the virtual disk size in VMware). Then open a command prompt and run diskpart without parameters.

To extend, you have to select the physical disk and volume. To know what to select, you can view the available disks and volumes.

List and select the physical disk:

DISKPART> list disk

  Disk ###  Status      Size     Free     Dyn  Gpt
  --------  ----------  -------  -------  ---  ---
  Disk 0    Online        20 GB      0 B

DISKPART> select disk 0

Disk 0 is now the selected disk.

List and select the volume:

DISKPART> list volume

  Volume ###  Ltr  Label        Fs     Type        Size     Status     Info
  ----------  ---  -----------  -----  ----------  -------  ---------  --------
  Volume 0     D                       DVD-ROM         0 B
  Volume 1     C                NTFS   Partition     20 GB  Healthy    System

DISKPART> select volume 1

Volume 1 is the selected volume.

When the right volume is selected, you can simply extend the volume to its maximum like so:

DISKPART> extend

You will get a message stating the result of the extension, depending on its success. If you get an error stating the volume cannot be extended, you may have selected the wrong volume.

Notice

Usually, it's not possible to extend the system volume (e.g. the C-drive) because it's permanently in use. If this is the case, you have to boot into recovery console (if it's not installed, use the installation disk of Win2003) and perform the extension from there.

Note that in Windows 2003, you cannot shrink a volume, only extend it.