diff --git a/README.md b/README.md
index 5c8966f..9abb5e0 100644
--- a/README.md
+++ b/README.md
@@ -282,6 +282,7 @@ You can create and attach additional disks to a VM via `libvirt.storage :file`.
 * `size` - Size of the disk image. If unspecified, defaults to 10G.
 * `type` - Type of disk image to create. Defaults to *qcow2*.
 * `bus` - Type of bus to connect device to. Defaults to *virtio*.
+* `cache` - Cache mode to use, e.g. `none`, `writeback`, `writethrough` (see the [libvirt documentation for possible values](http://libvirt.org/formatdomain.html#elementsDisks) or [here](https://www.suse.com/documentation/sles11/book_kvm/data/sect1_chapter_book_kvm.html) for a fuller explanation). Defaults to *default*.
 
 The following example creates two additional disks.
 
diff --git a/lib/vagrant-libvirt.rb b/lib/vagrant-libvirt.rb
index c7204d9..825e5fa 100644
--- a/lib/vagrant-libvirt.rb
+++ b/lib/vagrant-libvirt.rb
@@ -27,13 +27,3 @@ module VagrantPlugins
     end
   end
 end
-
-# set provider by bash env
-# export VAGRANT_DEFAULT_PROVIDER=libvirt
-Vagrant::Environment.class_eval do
-  def default_provider
-    (ENV['VAGRANT_DEFAULT_PROVIDER'] || :virtualbox).to_sym
-  end
-end
-
-
diff --git a/lib/vagrant-libvirt/config.rb b/lib/vagrant-libvirt/config.rb
index 48995c3..3186309 100644
--- a/lib/vagrant-libvirt/config.rb
+++ b/lib/vagrant-libvirt/config.rb
@@ -142,7 +142,8 @@ module VagrantPlugins
           :type => options[:type],
           :size => options[:size],
           :path => options[:path],
-          :bus => options[:bus]
+          :bus => options[:bus],
+          :cache => options[:cache] || 'default',
         }
 
         if storage_type == :file
diff --git a/lib/vagrant-libvirt/templates/domain.xml.erb b/lib/vagrant-libvirt/templates/domain.xml.erb
index 6c3bda8..1db5894 100644
--- a/lib/vagrant-libvirt/templates/domain.xml.erb
+++ b/lib/vagrant-libvirt/templates/domain.xml.erb
@@ -36,7 +36,7 @@
 <%# additional disks -%>
 <% @disks.each do |d| -%>
     <disk type='file' device='disk'>
-      <driver name='qemu' type='<%= d[:type] %>'/>
+      <driver name='qemu' type='<%= d[:type] %>' cache='<%= d[:cache] %>'/>
       <source file='<%= d[:path] %>'/>
       <target dev='<%= d[:device] %>' bus='<%= d[:bus] %>'/>
 <%# this will get auto generated by libvirt
diff --git a/vagrant-libvirt.gemspec b/vagrant-libvirt.gemspec
index 8c19f9c..e72b53b 100644
--- a/vagrant-libvirt.gemspec
+++ b/vagrant-libvirt.gemspec
@@ -21,7 +21,7 @@ Gem::Specification.new do |gem|
   gem.add_development_dependency "rspec-mocks", "~> 2.12.1"
 
   gem.add_runtime_dependency 'fog', '~> 1.15'
-  gem.add_runtime_dependency 'ruby-libvirt', '~> 0.4.0'
+  gem.add_runtime_dependency 'ruby-libvirt', '~> 0.4'
   gem.add_runtime_dependency 'nokogiri', '~> 1.6.0'
 
   gem.add_development_dependency 'rake'