VMFS Recovery

Recovers data from ESX server

Free VMFS Reader tool for MacOs/Windows/Linux

This is no wonder, that VMware keeps on gaining popularity among office environments. A dedicated virtual machine file system (VMFS) operates as both: a file system and a volume manager.  ESX and ESXi Server file-locking mechanism, also known as SCSI reservation, preserves the integrity of data contained on a volume. As soon as everything is based on supervisor-based virtual environments such as ESXi Server, a question of current importance suddenly pops up: is it possible to get access to VMware formatted file systems from other popular operating systems, without installing ESX/ESXi software.

A problem emerges when you face a rapid “system down” situation, and the urgency of accessing VMFS data is crucial. Unfortunately, if you deal with more than one VMware server environment, you won't be able to remap the logical unit number (LUN) into another VMware system really fast.

So the most reasonable solution would be to access the desirable data via Open Source VMFS driver. This VMFS Java application allows the users to access files and folders on partitions formatted with the VMFS when there are only non-VMware hosts around. A relative weakness of this driver that should be taken into consideration is that it works well only when the VM disks are not damaged. If a VM disc is corrupted or you have to deal with deleted files it would be more appropriate to use VMFS Recovery™. It recovers VMDK images created in all versions of ESX Server or VMware from healthy and corrupted VMFS disks, VMFS drives on faulty RAID arrays, and inaccessible hard drives, recovers data bypassing Windows access restrictions.

The VMFS driver is supplied with command-line interface (CLI) tools to mount and analyze VMFS volumes. It was tested on Linux and Windows-based hosts and is supposed to work on any platform supporting Java.


For accessing VMFS under Windows you are to have Java 6 Runtime Environment installed on your computer, as soon as all the tests, concerning this issue, were performed on it. To make sure that everything is installed correctly, execute “java-version” on the command line.

Download the latest version of fvmfs.jar distribution, and unzip the file into the desired location, for example, C:\Data Store

How to Run

Before you start, you have to make sure what physical drive number Windows has assigned to the VMWare drive, using Windows Disk Management. Run through the following steps: Computer Management - Storage - Disk Management to find a disk titled “Unknown Partition” and memorize its number. You'll need the disk number to mount it later.

Run a Command Line as administrator.

Test the VMFS driver by launching the following commands:

  cd \vmfs 
  java -jar fvmfs.jar   

Assuming that your operating system assigned number 3 to a target VMWare drive, check if you can get access to it by executing:

  java -jar fvmfs.jar  \\.\PhysicalDrive3 info

To hook the VMFS driver to the target drive type:

  java -jar fvmfs.jar \\.\PhysicalDrive1 webdav

If everything goes just right and the VMFS volume that you are trying to access is not damaged so that the driver can read it, a small web server will be launched to offer you both: WEBDAV access and regular HTTP access via browser to the data on the disc.

Now you can mount the drive either through a webdav (check if the webclient service is running) or by launching your web browser and typing:


The desired VMFS drive is successfully mounted, its content is available in read-only mode.

Basically this driver is the first open solution driver to access VMFS formatted volumes from any Linux, Windows or OS-X operating system (actually from any OS that allows running Java and mounting a volume)

Mounting on Linux

On Linux, the volume can be mounted using the davfs2 driver as follows:

  mount -t davfs -o ro http://localhost:50080/vmfs/ /mount/vmfs
  Please enter the username to authenticate with server
  http://localhost:50080/vmfs/ or hit enter for none.
  mount.davfs: warning: the server does not support locks

When asked for the username, skip, pressing ENTER, as soon as no authentication required. The volume is now accessible under the given mount point (/mount/vmfs in the above example).

Mounting on MAC OS X

For Mac OSX Users: everything works pretty similar to Linux, just use the "rdisk", e.g. /dev/rdisk4s1. If you plug in the disk you'll see it in "Disk Utility". If a laptop is used, you can get a USB->SATA converter and it works just fine.

Please, bear in mind, that the Open Source VMFS driver provides access to the healthy VMFS partitions and won't work with seriously damaged drives.

Download free VMFS driver, to solve more serious problems use Diskinternals VMFS Recovery™ tool.