Performance issues on Windows virtual machine with hardware version 13 after upgrading to ESXi 6.5

Products

• VMware vSphere ESXi

Issue/Introduction

This article provides steps against a specific issue which can affect the performance of a guest operating system in your virtual machine. While the recommendations can help you with improving this performance, there might still be other factors contributing to the issue you are experiencing, which will require further troubleshooting.

Symptoms:

After upgrading to VMware ESXi 6.5.0 P01 (build 5146846) or ESXi 6.5.0d (build 5310538), you experience these symptoms:

• Windows Server 2012 R2/Windows Server 2016 virtual machines respond slowly or appear to be unresponsive.
  Note: Windows 2008 R2 virtual machines are not affected.
• Applications running on the Windows Guest OS, such as an Exchange or File server run slowly.
• Virtual machine performance is degraded.

Environment

VMware vSphere ESXi 6.5

Cause

The issue occurs when non-aligned unmap requests are received from Guest OS under certain conditions depending on size and number of non-aligned unmaps. You may see the issue while deleting large number of small files ( less than 1 MB in size) in the Guest OS.

Resolution

This issue is resolved in VMware ESXi 6.5 Update 1. For more information, see the ESXi 6.5 Update 1 Release Notes.

 

Workaround:

Disable delete notification using one of these methods:

• Using a registry editor, change this key to 1:
  
  HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\FileSystem\DisableDeleteNotification
   
• Use this PowerCLI command:
  
  fsutil behavior set DisableDeleteNotify 1

Note: This is a temporary workaround to confirm the issue is seen when the Guest OS sends unmap requests.

Additional Information

• See Download Broadcom products and software for information on downloading. 
• For more information on using fsutil, see Microsoft Technet - Fsutil behavior.