Skip to main content

This Site will be down for up to 3 hours on December 2, 2023 from 8 PM - 11 PM PST, to deploy an infrastructure update.

NetApp Knowledge Base

Disk bottleneck may impact VMware LUN performance and timeouts

Last Updated:

Applies to

  • ONTAP 9
  • VMware ESXi
  • NFS, iSCSI, or FCP Datastores


  • Significant performance issues for NFS volumes, or FCP or iSCSI LUNs on a VMWare ESXi cluster or also iSCSI LUN timeouts
  • VMs are slow on reads or writes
  • qos statistics shows high disk latency
    • Example: vol1 has high disk latency

Workload            ID    Latency    Network    Cluster       Data     Disk    QoS Max    QoS Min      NVRAM  
--------------- ------ ---------- ---------- ---------- ---------- ---------- ---------- ---------- ----------
-total-              -     4.33ms   198.00us     9.00us  1221.00us     2.88ms        0ms        0ms    13.00us
vol1             32140   177.16ms   113.00us   226.00us   108.03ms    68.79ms        0ms        0ms     2.00us


Sign in to view the entire content of this KB article.

New to NetApp?

Learn more about our award-winning Support

NetApp provides no representations or warranties regarding the accuracy or reliability or serviceability of any information or recommendations provided in this publication or with respect to any results that may be obtained by the use of the information or observance of any recommendations provided herein. The information in this document is distributed AS IS and the use of this information or the implementation of any recommendations or techniques herein is a customer's responsibility and depends on the customer's ability to evaluate and integrate them into the customer's operational environment. This document and the information contained herein may be used solely in connection with the NetApp products discussed in this document.
Scan to view the article on your device