Mount CephFS on Windows

ceph-dokan can be used for mounting CephFS filesystems on Windows. It leverages Dokany, a Windows driver that allows implementing filesystems in userspace, pretty much like FUSE.

Please check the installation guide to get started.


Mounting filesystems

In order to mount a ceph filesystem, the following command can be used:

ceph-dokan.exe -c c:\ceph.conf -l x

This will mount the default ceph filesystem using the drive letter x. If ceph.conf is placed at the default location, which is %ProgramData%\ceph\ceph.conf, then this argument becomes optional.

The -l argument also allows using an empty folder as a mountpoint instead of a drive letter.

The uid and gid used for mounting the filesystem default to 0 and may be changed using the following ceph.conf options:

# client_permissions = true
client_mount_uid = 1000
client_mount_gid = 1000

If you have more than one FS on your Ceph cluster, use the option --client_fs to mount the non-default FS:

mkdir -Force C:\mnt\mycephfs2
ceph-dokan.exe --mountpoint C:\mnt\mycephfs2 --client_fs mycephfs2

CephFS subdirectories can be mounted using the --root-path parameter:

ceph-dokan -l y --root-path /a

If the -o --removable flags are set, the mounts will show up in the Get-Volume results:

PS C:\> Get-Volume -FriendlyName "Ceph*" | `
        Select-Object -Property @("DriveLetter", "Filesystem", "FilesystemLabel")

DriveLetter Filesystem FilesystemLabel
----------- ---------- ---------------
          Z Ceph       Ceph
          W Ceph       Ceph - new_fs

Please use ceph-dokan --help for a full list of arguments.


The --id option passes the name of the CephX user whose keyring we intend to use for mounting CephFS. The following commands are equivalent:

ceph-dokan --id foo -l x
ceph-dokan --name -l x

Unmounting filesystems

The mount can be removed by either issuing ctrl-c or using the unmap command, like so:

ceph-dokan.exe unmap -l x

Note that when unmapping Ceph filesystems, the exact same mountpoint argument must be used as when the mapping was created.


Be aware that Windows ACLs are ignored. Posix ACLs are supported but cannot be modified using the current CLI. In the future, we may add some command actions to change file ownership or permissions.

Another thing to note is that cephfs doesn’t support mandatory file locks, which Windows is heavily rely upon. At the moment, we’re letting Dokan handle file locks, which are only enforced locally.

Unlike rbd-wnbd, ceph-dokan doesn’t currently provide a service command. In order for the cephfs mount to survive host reboots, consider using NSSM.


Please consult the Windows troubleshooting page.