Cloning a VM there is slowness in the VM OS and VM high C drive usage whenon NFS storage

Products

• VMware vSphere ESXi

Issue/Introduction

When the administrator clones a VM while the original VM is still running and it resides on NFS storage, it experiences slowness in the VM OS and VM high C drive active usage

Environment

vSphere ESXi (All versions)

 

Cause

Looking in the /var/log/vmkernal.log shows entries that look similar to:

WARNING: NFS: 5072: NFS volume ########### average I/O latency 35956(us) has exceeded threshold 10000(us) for last 10 minutes

Resolution

Recommended that the customer to check on any IO latency on the NFS storage and they were able to confirm the problem was on the NFS storage NAS. 

Also, see the reference KB Interpreting NFS datastore's latencies related messages in vmkernel logs