vSAN health alerts triggered for Cluster partition and vSAN MTU Check (ping with large packet size)

Products

• VMware vSAN

Issue/Introduction

Symptoms:

The following alerts were observed in vSAN Skyline Health for cluster:

• vSAN: Cluster partition

• vSAN: MTU Check (ping with large packet size)

• Further verification show that the host is not reachable from other hosts in the cluster over vsan vmkernel.

 

Environment

• VMware ESXi 8.x
• VMware ESXi 9.x

Cause

The ESXi loses the vSAN service tag on the vmkernel adapter after a host profile update. Because of this, the host will not be able to communicate with other ESXi hosts over the vSAN network.

The /var/run/log/hostd.log confirms that the vSAN network configuration was removed while applying the host profile.

2026-02-09T14:26:23.899Z In(166) Hostd[2101780]: [Originator@6876 sub=Vimsvc.TaskManager opID=mh3j8th7-11003875-auto-6juqi-h5:70695286-3d-01-f5-e8dc sid=52f48f39 user=vpxuser:<no user>] Task Created : haTask--vim.profile.host.profileEngine.HostProfileManager.applyHostConfig-4193179384

2026-02-09T14:26:25.303Z In(166) Hostd[2102504]: [Originator@6876 sub=Hostsvc.VmkVprobSource] VmkVprobSource::Post event: (vim.event.EventEx) {
2026-02-09T14:26:25.303Z In(166) Hostd[2101766]: -->    key = 192,
2026-02-09T14:26:25.303Z In(166) Hostd[2101766]: -->    chainId = 2012480792,
2026-02-09T14:26:25.303Z In(166) Hostd[2101766]: -->    createdTime = "1970-01-01T00:00:00Z",
2026-02-09T14:26:25.303Z In(166) Hostd[2101766]: -->    userName = "",
2026-02-09T14:26:25.303Z In(166) Hostd[2101766]: -->    host = (vim.event.HostEventArgument) {
2026-02-09T14:26:25.303Z In(166) Hostd[2101766]: -->       name = "esxi_hostname",
2026-02-09T14:26:25.303Z In(166) Hostd[2101766]: -->       host = 'vim.HostSystem:ha-host'
2026-02-09T14:26:25.303Z In(166) Hostd[2101766]: -->    },
2026-02-09T14:26:25.303Z In(166) Hostd[2101766]: -->    eventTypeId = "esx.audit.vsan.net.vnic.deleted",
2026-02-09T14:26:25.303Z In(166) Hostd[2101766]: -->    objectId = "ha-host",
2026-02-09T14:26:25.303Z In(166) Hostd[2101766]: -->    objectType = "vim.HostSystem",
2026-02-09T14:26:25.303Z In(166) Hostd[2101766]: --> }
2026-02-09T14:26:25.303Z In(166) Hostd[2102504]: [Originator@6876 sub=Vimsvc.ha-eventmgr] Event 332 : vSAN network configuration has been removed. The host may experience problems communicating with other hosts in vSAN cluster.

Additionally, the /var/run/log/vmkernel.log confirms that vmkernel is removed from the CMMDS database, which is required for vSAN cluster communication.

2026-02-09T14:26:25.201Z In(182) vmkernel: cpu67:2099049)CMMDSNet: CMMDSNet_ContextRemoveInterface:780: 529d9b62-0f93-52f9-4e38-#######: Removing Interface for context 529d9b62-0f93-52f9-4e38-#######: vmk1
2026-02-09T14:26:25.201Z In(182) vmkernel: cpu67:2099049)CMMDS: CMMDSVSIUpdateNetworkCbk:4035: 529d9b62-0f93-52f9-4e38-#######: DELETE of interface vmk1 with cmmds (Success).
2026-02-09T14:26:25.206Z In(182) vmkernel: cpu67:2099049)CMMDS: CMMDSUtil_PrintArenaEntry:52: 529d9b62-0f93-52f9-4e38-#######: [541324]:Removing actDir:0 u:529d85ae-0ed7-9ced-f06c-####### o:685ea452-7a6f-6306-9b4b-####### r:0 t:NET_INTERFACE

Further validate the vmkernel configuration on ESXi host confirm that vSAN traffic is not enabled on the vmkernel adapter.

Resolution

• Enable vSAN traffic on vmkernel for the affected ESXi host.

• Before applying a host profile, always verify that the correct vmkernel service tags (vSAN, Management, vMotion, etc.) are properly configured.