I wanted to resize a VMDK, which VBoxManage can't resize directly, so I used the Convert to VDI → Resize VDI → Convert to VMDK procedure described here.

For the last step, I could not find clear documentation of which --variant corresponded to the "dynamically allocated" option I chose in the GUI when creating the original VMDK.

The documentation on clonehd has this list of variants: Standard, Fixed, Split2G, Stream, ESX. It is not obvious from the names which of those is dynamically allocated, and there is no mention of which variants apply to which image formats.

The documentation on disk image files refers to the GUI options of "fixed-size" or "dynamically allocated", but uses the word "variant" to mean file format, and does not refer to the list above or any of its entries.

Which --variant corresponds to selecting "dynamically allocated" in the GUI?

This is with VirtualBox 5.0.32 r112930 on macOS Sierra 10.12.3 (16D32)

  • There is a relevant discussion in this forum thread, but it's old, doesn't have a clear answer, doesn't link the documentation it quotes, and devolves into pointless arguments. Feb 3, 2017 at 18:53

1 Answer 1


According to this forum post:

  • Standard (the default) - one piece dynamic (sparse) extent file, plus a small descriptor file.
  • Fixed - extents will be flat (rather than dynamic/sparse).
  • Split2G - image is split into multiple extents, each less than 2GB.
  • Stream - image is optimized for streaming downloads rather than running in a VM. This type may be compressed.
  • ESX ?

so standard is you proper option or no --variant at all since standard is the default.

  • Having created the disk and seen the file size much smaller than the increased capacity, it looks like your conclusion is correct. But where the heck did they find that information? Feb 3, 2017 at 19:49

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