The host cannot enter maintenance mode. Resource check failed - vSAN 4-node cluster
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The host cannot enter maintenance mode. Resource check failed - vSAN 4-node cluster

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Article ID: 397437

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Updated On:

Products

VMware vSAN VMware vSAN 7.x VMware vSAN 8.x

Issue/Introduction

When attempting to place an ESXi host into Maintenance Mode with Full Data Evacuation in a 4-node vSAN cluster, the task fails with the following error: The host cannot enter maintenance mode. Resource check failed - There are currently 3 usable fault domains. The operation requires 1 more usable fault domain.

A pre-check may also identify specific failed objects: Sample failed object: ####-####-####-#### 1 more standalone host is required. Some objects will become inaccessible or non-compliant with their storage policy.

The clomd.log on the ESXi host will contain the following error message confirming the resource constraint: LOM_CheckClusterResourcesForPolicy: Not enough Upper FD's available. Available: 3, needed: 4



 
 

Environment

  • VMware vSAN 7.x OSA
  • VMware vSAN 8.x OSA
  • 4-node vSAN cluster

Cause

The failure is caused by a Storage Policy Based Management (SPBM) constraint. If any virtual disks or objects in the cluster are assigned a RAID-5 (Erasure Coding) FTT=1 storage policy, a minimum of 4 fault domains (hosts) is strictly required to maintain data availability. Placing one host into maintenance mode reduces the available fault domains to 3, violating the RAID-5 placement rules.

Resolution

To decommission or place a host into maintenance mode, convert the storage policy of RAID-5 objects to RAID-1 (Mirroring).

  1. Identify problematic objects using the ESXi CLI: esxcli vsan debug object list --all | grep RAID_5
  2. vMotion unrelated workloads to an external datastore (e.g., NFS) if necessary to free up transient resync space.
  3. In the vSphere Client, navigate to the affected VMs.
  4. Change the VM Storage Policy from RAID-5 (FTT=1) to RAID-1 (FTT=1).
  5. Perform the conversion sequentially (one disk or one VM at a time).
  6. Monitor the vSAN resync dashboard. Ensure the resync completes fully before starting the next object.
  7. Once all objects are compliant under the RAID-1 policy, re-attempt placing the host into maintenance mode.

Note: For VCF (VMware Cloud Foundation), subscribe to this article to be updated on fix status: https://knowledge.broadcom.com/external/article/275360.

Additional Information

Related Documentation:

Troubleshooting References:

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