Synced folder type: smb

Vagrant can use SMB as a mechanism to create a bi-directional synced folder between the host machine and the Vagrant machine.

SMB is built-in to Windows machines and provides a higher performance alternative to some other mechanisms such as VirtualBox shared folders.

Windows only! SMB is currently only supported when the host machine is Windows. The guest machine can be Windows or Linux.


To use the SMB synced folder type, the machine running Vagrant must be a Windows machine with PowerShell version 3 or later installed. In addition to this, the command prompt executing Vagrant must have administrative privileges. Vagrant requires these privileges in order to create new network folder shares.

The destination machine must be able to mount SMB filesystems. On Linux the package to do this is usually called smbfs or cifs. Vagrant knows how to automatically install this for some operating systems.


The SMB synced folder type has a variety of options it accepts:

  • smb_host (string) - The host IP where the SMB mount is located. If this is not specified, Vagrant will attempt to determine this automatically.

  • smb_password (string) - The password used for authentication to mount the SMB mount. This is the password for the username specified by smb_username. If this is not specified, Vagrant will prompt you for it. It is highly recommended that you do not set this, since it would expose your password directly in your Vagrantfile.

  • smb_username (string) - The username used for authentication to mount the SMB mount. This is the username to access the mount, not the username of the account where the folder is being mounted to. This is usually your Windows username. If you sign into a domain, specify it as user@domain. If this option is not specified, Vagrant will prompt you for it.


The following is an example of using SMB to sync a folder:

Vagrant.configure("2") do |config|
  config.vm.synced_folder ".", "/vagrant", type: "smb"

Preventing Idle Disconnects

On Windows, if a file is not accessed for some period of time, it may disconnect from the guest and prevent the guest from accessing the SMB-mounted share. To prevent this, the following command can be used in a superuser shell. Note that you should research if this is the right option for you.

net config server /autodisconnect:-1


Because SMB is a relatively new synced folder type in Vagrant, it still has some rough edges. Hopefully, future versions of Vagrant will address these.

The primary limitation of SMB synced folders at the moment is that they are never pruned or cleaned up. Once the folder share is defined, Vagrant never removes it. To clean up SMB synced folder shares, periodically run net share in a command prompt, find the shares you do not want, then run net share NAME /delete for each, where NAME is the name of the share.

Common Issues

"wrong fs type" Error

If during mounting on Linux you are seeing an error message that includes the words "wrong fs type," this is because the SMB kernel extension needs to be updated in the OS.

If updating the kernel extension is not an option, you can workaround the issue by specifying the following options on your synced folder:

mount_options: ["username=USERNAME","password=PASSWORD"]

Replace "USERNAME" and "PASSWORD" with your SMB username and password.

Vagrant 1.8 changed SMB mounting to use the more secure credential file mechanism. However, many operating systems ship with an outdated filesystem type for SMB out of the box which does not support this. The above workaround reverts Vagrant to the insecure before, but causes it work.

© 2010–2017 Mitchell Hashimoto
Licensed under the MPL 2.0 License.