Error: Virtual object reduced availability with no rebuild due to fractional disk size in vSAN ESA

Products

• VMware vSAN

Issue/Introduction

In a VMware vSAN Express Storage Architecture (ESA) cluster, a virtual object reports a status of reduced-availability-with-no-rebuild.

Specific symptoms include:

• Automatic cluster rebuilds fail to initiate.
• The object compliance state is marked as Non-Compliant.
• Manual resynchronization does not trigger active data movement.
• The esxcli vsan debug object health summary get command shows one or more objects in the reduced-availability-with-no-rebuild state.
• Attempts to resize the virtual disk to a whole-number integer (e.g., from 2.001 TB to 2.1 TB) fail.

Environment

• VMware vSAN 8.x (ESA)
• VMware ESXi 8.0.3 and higher

Cause

The issue is caused by a fractional virtual disk allocation size (e.g., 2.001 TB) which generates a block alignment mismatch within vSAN ESA. This mathematical misalignment, combined with a metadata database conflict where the object tracks two conflicting storage policies simultaneously  causes the vSAN Distributed Object Manager (DOM) to freeze policy compliance updates.

Resolution

This issue is addressed in VMware vSAN 8.0 Update 3 and higher. See Download Broadcom products and software for steps to download the latest release.

To remediate a stuck object in an existing environment, perform the following steps:

1. Clone the Storage Policy: Create a clone of the baseline storage policy template intended for the virtual object.
2. Re-apply Policy: Apply the cloned storage policy directly to the virtual machine. This forces a metadata rewrite within the Cluster Management Monitor and Directory Services (CMMDS) and decouples the conflicting policy mappings.
3. Full VM Clone (if needed): If the object remains unaligned or configuration changes continue to fail, perform an end-to-end virtual machine clone to a newly provisioned, whole-number block storage target (e.g., 2 TB instead of 2.001 TB).
4. Decommission Stale Object: Once the cloned VM is validated as healthy, execute an object purge command to safely decommission the degraded components.

Additional Information

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