Increasing the size of a virtual disk partition
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Increasing the size of a virtual disk partition

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Article ID: 323136

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Updated On:

Products

VMware VMware Desktop Hypervisor VMware vCenter Server VMware vSphere ESXi

Issue/Introduction

Extending a virtual disk only extends a virtual machine's disk. This does not automatically increase the size of the file system (such as NTFS for Windows and ext3 for Linux) within the guest. 

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.

Symptoms:
  • You need to increase the size of a virtual 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.

Resolution

You can expand the size of the VMDK disk while the virtual machine is online. However, you must reboot the guest operating system (OS) in the virtual machine so that it is aware of the size change of the VMDK disk.

Also, ensure that the virtual machine is not running on snapshots, as this prevents the VMDK from being extended.

To verify if the virtual machine is running on snapshot disks:

  1. Right-click the virtual machine and click Edit Settings.
  2. Select the Virtual Disk and check the Disk File. If it is labeled as VM-000001.vmdk, the virtual machine is running on snapshot disks.

Depending on the guest OS in the virtual machine, there are several methods available to increase the file system within the virtual machine.
 

Extending a Windows guest file system

Note: Windows Server 2008, Windows Server 2008 R2, Windows Vista, Windows 7, Windows 8 and Windows Server 2012, Windows 8.1, Windows 10, Windows Server 2012 R2, Windows Server 2016 and Windows Server 2019 can expand the volumes from the Disk Management in Computer Management. Right-click on Volume and click Extend Volume. For more information, see Microsoft's documentation. Instead of rebooting the guest operating system, in Computer Management, right-click Disk Management and click Rescan Disks.
 
  • If the partition you are extending in the virtual machine contains a different version of Windows, you may need to use a 3rd party tool 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 machine 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 information on extending a VMDK disk using DiskPart, see the Microsoft documentation: Extend a data volume in Windows
If you encounter a situation where you add more storage to an existing virtual machine'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. 
 
Note: 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 ext4 or xfs 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 information on extending an ext4 or xfs file system with LVM, see RedHat's documentation:  Growing a File System on a Logical Volume.

If you are running a file system that is not uner the control of the LVM, 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

Name Link to the Tool
DFSee http://www.dfsee.com/dfsee/index.php
EASEUS Partition Manager http://www.partition-tool.com/
GParted LiveCD http://gparted.sourceforge.net/livecd.php
Partition Logic http://partitionlogic.org.uk/
Paragon Partition Manager http://www.partition-manager.com/
System Rescue CD http://www.sysresccd.org/Main_Page
Windows DiskPart utility If 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.

Notes:

  • VMware does not endorse or recommend any particular third party utility, nor is the above list meant to be exhaustive.

Additional Information

  • VMware command line utilities used to resize virtual disks do not touch the data or partitions inside the virtual disks. Any desired partition changes must be made from the virtual machine's operating system.

  • Growing a File System on a Logical Volume

  • Extend a data volume in Windows

  • 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.
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