Vagrant plugin to resize disks in VirtualBox
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Simon Protheroe
Latest commit 56b46a9 Oct 26, 2018


A Vagrant plugin to resize disks in VirtualBox


vagrant plugin install vagrant-disksize


Set the size you want for your disk in your Vagrantfile. For example

Vagrant.configure('2') do |config| = 'ubuntu/xenial64'
  config.disksize.size = '50GB'

You can specify the size as a raw number (in bytes) or using KB, MB, GB or TB (though I'd be interested to learn more if you are using Vagrant to create multi-terabyte disks). Internally the size will be converted to megabytes, for ease of interaction with VirtualBox. If the value you specify isn't a whole number of megabytes, it will be rounded up, to ensure you have at least the capacity you requested. Note that the plugin uses the original definitions so, for example, 1 GB = 1024 MB; we don't have to use hardware manufacturer marketing maths here and it makes the internal maths easier.


At present only the first disk will be resized. That seems to be OK for typical boxes such as the official Ubuntu images for Xenial, but there may well be other configurations where the first disk found isn't the main HDD.

The plugin only works with VirtualBox but it will issue an error message and then disable itself if you try to use it with another provider.

Disks can only be increased in size. There is no facility to shrink a disk.

Depending on the guest, you may need to resize the partition and the filesystem from within the guest. At present the plugin only resizes the underlying disk.

This hasn't been tested on a wide variety of versions of Vagrant or VirtualBox. It works for, at least, Vagrant 1.8.5 and VirtualBox 5.1.x, but any feedback about other versions, particularly older ones, would be much appreciated.


After checking out the repo, run bin/setup to install dependencies. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to


Bug reports and pull requests are welcome on GitHub at


The gem is available as open source under the terms of the MIT License.