Increasing the size of a disk partition

Symptoms

  • You need to increase the size of a disk partition.
  • You have increased the size of a virtual disk but can see no increase in available space in virtual machine.
  • The partition does not increase with the increase in disk size.
  • You cannot see new disk space.
  • Expanding a virtual disk does not work.

Purpose

Extending a virtual disk only extends a virtual machine's disk it will not automatically increase the size of the file system (such as NTFS for Windows and ext3 for Linux) within the guest. For more information on how to extend the virtual disk, see the documentationfor your VMware product.

This article describes increasing the size of a disk partition. The virtual disk may have unallocated space that you now want to use. You may also have increased the size of a virtual machine's virtual disk but are unable to see the new space from the virtual machine's operating system.

Resolution

While you can expand the size of the VMDK disk while the virtual machine is online you will need to reboot the guest OS in the virtual machine so that the guest OS is aware of the change in size of the VMDK disk.
You also need to ensure that your virtual machine is not running on snapshots as it will prevent the VMDK being extended.

Depending on the guest OS in the virtual machine there are a number of methods of increasing the file system within the virtual machine.

Extending a Windows guest file system

If the partition you are extending in the virtual machine contains the Windows Operating System then you may need to use a 3rd party tool (a number of 3rd party tools are mentioned below) to extend the partition.

If you have another Windows virtual machine with the same version of the Operating System you could temporarily attach the Operating System VMDK to this virtual machine (known as a helper VM) and extend the file system on the VMDK from this virtual using the Windows DiskPart tool.

If the VMDK disk you need to extend does not contain the Operating System disk then you can use DiskPart in the original virtual machine without the need for a helper VM.

For more/related information on extending a VMDK disk using DiskPart, see Extending partitions in Windows using DiskPart (1007266).

Note: Windows Server 2008, Windows Server 2008 R2, Windows Vista, and Windows 7 can expand the volumes from the Disk Manager in Computer Management. Right-click on volume and click Extend Volume. For more information, see Microsoft's documentation.

If you encounter a situation where you add more storage to an existing VM's disk volume, and DISKPART allows you to (apparently) successfully extend the volume, and yet from Windows Explorer, the disk still shows the original size, check to ensure that the volume you are trying to extend does not contain the page file. For more information, see the restrictions on volume extending in the Microsoft Knowledge Base article 325590, specifically:

"You cannot extend the partition if the system page file is located on the partition. Move the page file to a partition that you do not want to extend."


Extending a Linux guest file system

If the Linux virtual machine has an ext3 file system under the control of Logical Volume Manager (LVM) control then there are LVM tools to allow the file system to be extended.
For more/related information on extending an ext3 file system with LVM, see Extending a logical volume in a virtual machine running Red Hat or Cent OS (1006371)

If you are running a file system other then ext3 you may need to research an alternative way of accomplishing this.
Reiser has its own tool for accomplishing this, GParted Live CD is another popular tool for this.


Examples of third-party utilities

7tools Partition Managerhttp://www.7tools.com/pm/index.htm
DFSeehttp://www.dfsee.com/dfsee/index.php
EASEUS Partition Managerhttp://www.partition-tool.com
GParted LiveCDhttp://gparted.sourceforge.net/livecd.php
Partition Logichttp://partitionlogic.org.uk
Paragon Partition Managerhttp://www.partition-manager.com
Ranish Partition Managerhttp://www.ranish.com/part
System Rescue CDhttp://www.sysresccd.org/Main_Page
Windows DiskPart utilityIf you are using the Windows DiskPart utility, it can only extend (expand) data volumes. If you use the DiskPart utility to extend a system or boot volume, you may get an error. For more information about extending partitions with the DiskPart utility, see the Microsoft Knowledge Base article 325590.

Notes:

  • VMware does not endorse or recommend any particular third party utility, nor is the above list meant to be exhaustive.
  • The preceding links were valid as of June 19, 2009. If you find the links to be broken, provide feedback on the article and a VMware employee will update the article as necessary.

THE CONTENT OF THIS ARTICLE IS PROVIDED "AS-IS," AND TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, VMWARE DISCLAIMS ALL OTHER REPRESENTATIONS AND WARRANTIES, EXPRESS OR IMPLIED, REGARDING THIS CONTENT, INCLUDING THEIR FITNESS FOR A PARTICULAR PURPOSE, THEIR MERCHANTABILITY, OR THEIR NONINFRINGEMENT. VMWARE SHALL NOT BE LIABLE FOR ANY DAMAGES ARISING OUT OF OR IN CONNECTION WITH THE USE OF THIS CONTENT, INCLUDING DIRECT, INDIRECT, CONSEQUENTIAL DAMAGES, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF VMWARE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES.

Based on VMware KB 1004071

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