ESXi includes VMFS version 3 (VMFS-3). If your datastore was formatted with VMFS-2, you can read files stored on VMFS-2, but you cannot write to them. To have complete access to the files, upgrade VMFS-2 to VMFS-3.

When you upgrade VMFS-2 to VMFS-3, the ESXi file-locking mechanism ensures that no remote host or local process is accessing the VMFS datastore being converted. Your host preserves all files on the datastore.

As a precaution, before you use the upgrade option, consider the following:

Commit or discard any changes to virtual disks in the VMFS-2 volume that you plan to upgrade.

Back up the VMFS-2 volume.

Be sure that no powered on virtual machines are using the VMFS-2 volume.

Be sure that no other ESXi host is accessing the VMFS-2 volume.

The VMFS-2 to VMFS-3 conversion is a one-way process. After you convert the VMFS-based datastore to VMFS-3, you cannot revert it back to VMFS-2.

To upgrade the VMFS-2 file system, its file block size must not exceed 8MB.


Log in to the vSphere Client and select a host from the Inventory panel.


Click the Configuration tab and click Storage.


Select the datastore that uses the VMFS-2 format.


Click Upgrade to VMFS-3.


Perform a rescan on all hosts that see the datastore.