It may be necessary at some point to increase the size of a virtual disk on a guest OS. Here’s how to do it without creating a new disk and migrating the data manually:

• Shut down the VM
• Expand the virtual disk
  • Log into the ESX server via ssh
  • Navigate to the guest’s storage location (ex: /vmfs/volumes/cx300/guest)
  • Use the vmkfstools command to expand the disk. For example:

vmkfstools -X 8g guest.vmdk

• Boot from the gparted LiveCD
  • Download the .iso to your desktop
  • Mount it on the virtual CD-ROM device
  • Select CD-ROM from boot menu
  • Select Xvesa from the boot options menu -> done
  • Select defaults from the remainder of the options
• Extend the partition
  • Use the gparted GUI to resize the ext3 partition
• Reboot into Linux