VMFS datastore won't mount on a newly added host in vCenter part of Host Cluster.

Products

• VMware vSphere ESXi

Issue/Introduction

A newly added host to the ESXi host cluster will not mount the VMFS datastore despite seeing the corresponding LUN on the ESXi host.

The VMFS datastore can be seen mounted on other ESXi hosts in the cluster.

The Corresponding LUNs are seen presented on the host.

The LUNs is not a snapshot.

 

 

Environment

VMware vSphere ESXi (all versions)

Cause

From the logs we see the VMFS datastore was already unmounted from the same host in the past hence the VMFS datastore won't auto-mount when a VMFS rescan is done from Cluster or Host directly.

Only option we have is to re-mount the datastore from UI or from Cli.

Look for the datastore unmounted message against that Datastore name from Hostd logs and Vmkernel logs:

Hostd log:

2025-04-23T11:27:46.528Z In(166) Hostd[2099202]: [Originator@6876 sub=Vimsvc.ha-eventmgr] Event 286: The volume [xxxx_xxxx_xxx_xxxxx_xxxx, xxxxxxx-xxxxxxx-xxxx-xxxxxxxxxxxx] has been safely un-mounted. The datastore is no longer accessible on this host.

2025-06-13T14:08:29.145Z In(166) Hostd[2099095]: [Originator@6876 sub=Libs] GetUnmountedVmfsFileSystems: There are 2 unmounted (NoSnaphot) volumes.

 

VMkernel log:

2025-04-23T11:23:43.102Z In(182) vmkernel: cpu6:2099277 opID=e795c437)LVM: 17753: File system '[[xxxx_xxxx_xxx_xxxxx_xxxx, xxxxxxxx-xxxxxxxx-xxxx-xxxxxxxxxxxx]' (LV xxxxxxxx-xxxxxxxx-xxxx-xxxxxxxxxxxx) un-mounted.

 

Since the datastore was already unmounted, hence a VMFS rescan will not auto mount a VMFS datastore back.

 

Resolution

Re-mount the datastore back from vCenter or host UI by Right clicking the datastore and click on Mount.

Select the host to mount:

 

Click Next.

OR you can re-mount the datastore from the CLI.

Note: The datastore name and UUID can be found from the Hostd or the vmkernel logs as described above.

From CLI:

esxcli storage filesystem mount -u <UUID>

esxcli storage filesystem mount -l <label>