If you use the auto-partitioning boot option when installing or auto-deploying ESXi, the auto-partitioning option creates a VMFS datastore on your host's local storage. In certain cases, you need to keep your local storage flash disks unformatted.


By default, auto-partitioning deploys VMFS file systems on any unused local storage disks on your host, including flash disks.

However, a flash disk formatted with VMFS becomes unavailable for such features as virtual flash and vSAN. Both features require an unformatted flash disk and neither can share the disk with any other file system.


To ensure that auto-partitioning does not format the flash disk with VMFS, use the following boot options when you install ESXi or boot the ESXi host for the first time:
  • autoPartition=TRUE
  • skipPartitioningSsds=TRUE
If you use Auto Deploy, set these parameters on a reference ESXi host.
  1. In the vSphere Client, navigate to the host to use as a reference host and click the Configure tab.
  2. Click System to open the system options, and click Advanced System Settings.
  3. Set the following items.
    Parameter Value
    VMkernel.Boot.autoPartition True
    VMkernel.Boot.skipPartitioningSsds True
  4. Reboot the host.

If flash disks that you plan to use with the virtual flash resource and vSAN already have VMFS datastores, remove the datastores.