vSAN Health Service - No disk claimed on witness host
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vSAN Health Service - No disk claimed on witness host


Article ID: 326422


Updated On:


VMware vSAN


The "No disk claimed on witness host" check in the vSAN Health Service verifies that the witness host has claimed a disk group. If this health check is not green (OK), the vSAN stretched cluster has configuration errors that affect its operation and might impact data availability if another site failure occurs.

If the witness host does not have any disk claimed, its fault domain is not available and vSAN cannot provision any objects with Number of Failures To Tolerate set to 1 (FTT = 1).


VMware vSAN 6.x
VMware vSAN 7.0.x
VMware vSAN 8.0.x


To prevent or resolve the error state, add a disk group to the witness host.

Via vSphere Client

You can use the vSphere Web Client to configure a disk group for the witness host.
  1. In the Host and Clusters view, select the vSAN cluster.
  2. Click Manage > Settings.
  3. Under Virtual SAN/vSAN, click Disk Management.
  4. Select the witness host.
  5. Create a new disk group.


To create the disk group via CLI, you can use the following command
# esxcli vsan storage add -s <cache ID> -d <capacity ID>
To identify these IDs, run the command 
# esxcli storage core device list 
(In the witness, the storage device IDs usually appears as "mpx.hba0:C0:T0:L0")

# esxcli vsan storage add -s mpx.hba0:C0:T0:L0 -d mpx.hba0:C0:T1:L0

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