Slow Cloning and VM Deployment Operations on NFS Datastores
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Slow Cloning and VM Deployment Operations on NFS Datastores

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Article ID: 436007

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Updated On:

Products

VMware vSphere ESXi 8.0

Issue/Introduction

  • VM cloning operations take an excessive amount of time (e.g., 90 minutes for a 2 TB disk).
  • VM deployments from templates are slow or fail due to timeouts.
  • Storage latency (DAVG/KAVG) appears normal in `esxtop`.
  • The environment uses NFS datastores with a VAAI (vSphere Storage APIs for Array Integration) NAS plugin installed.
  • vmkernel.log` may contain NFC (Network File Copy) errors or failures when attempting to open files during the clone process.

    2026-03-23T20:43:19.120Z In(166) Hostd[2100944]: [Originator@6876 sub=Libs opID=#####-1324187-:#######-bd-01-####sid=52a04e26 user=vpxuser: [NFC ERROR]Nfc_DiskLib_Open: Failed to open '/vmfs/volumes/0fcdb1fa-#######-0000-000000000000/test--12tb-slow/test-<REDACTED_PII>-12tb-slow.vmdk': The system cannot find the file specified

Environment

VMware vSphere ESXi 8.0.3
NETAPP NAS Datastore
VAAI NAS Plugin

Cause

The issue is caused by a malfunction or incompatibility with the VAAI NAS plugin delaying storage operations.

Resolution

  1. Access the impacted ESXi host via SSH.

  2. Stop the VAAI NAS daemon to disable hardware acceleration for NFS and allow vSphere to handle the cloning operations using standard software data copy methods:

/etc/init.d/vaai-nasd stop

  1. Perform a test clone to verify performance improvements.

  2. Engage the storage vendor (NetApp) to investigate the specific version of the NAS plugin in use.

  3. Update the NAS plugin to a version compatible with VMware ESXi 8.0.3.
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