VMFS 5/6 Datastore Maximum Supported Capacity
search cancel

VMFS 5/6 Datastore Maximum Supported Capacity

book

Article ID: 410951

calendar_today

Updated On:

Products

VMware vCenter Server

Issue/Introduction

The maximum supported capacity for a single VMFS5 or VMFS6 datastore is 64 TB. While certain storage arrays allow the creation of LUNs and subsequent VMFS volumes exceeding this limit, such configurations are unsupported and lead to operational instability. This article details the symptoms, risks, and required resolutions for datastores exceeding supported limits.

Symptoms

  • Space Reclamation Stalls: Asynchronous UNMAP operations stop or fail to reclaim the full extent of deleted data.
  • Snapshot Performance: Significant increase in "stun" duration during virtual machine snapshot creation or deletion (e.g., stun times exceeding 7 seconds).
  • Backup/Restore Failures: VM restore tasks via NetBackup or other VADP-based solutions fail when targeting non-compliant datastores.
  • Operational Instability: Metadata corruption or datastore volume becoming unresponsive/locking up.
  • UI Alerts: The vSphere Client reports datastore capacity above 64 TB.

Environment

  • VMware ESXi 7.x
  • VMware ESXi 8.x
  • VMFS5 and VMFS6 Datastores

Cause

VMFS filesystem metadata structures are neither validated nor tested for capacities beyond 64 TB. When a volume exceeds this limit, metadata-intensive tasks—such as space reclamation and disk lock upgrades for snapshots—encounter integrity risks. While ESXi does not always prevent the creation of these volumes, it cannot guarantee data consistency or performance.

Resolution

To restore a supported state and ensure data integrity, the datastore must be brought within the 64 TB limit.

  1. Migrate Data: Use Storage vMotion to move all virtual machines from the non-compliant datastore to new volumes that are 64 TB or smaller.
    • Note: Standard Storage vMotion may encounter timeouts on ultra-large volumes over 10 GbE networks. Consider application-level replication for extremely large payloads.
  2. Reconfigure Storage: Delete the non-compliant VMFS volume and reconfigure the underlying storage LUNs to not exceed 64 TB.
  3. Alternative Storage: For single-namespace requirements exceeding 64 TB, utilize VMware vSAN or Virtual Volumes (vVols).

Additional Information

Powered by Wolken Software