Dynamic Environment Manager slow logon and logoff performance when using EMC filers

Products

• VMware Horizon 8

Issue/Introduction

Symptoms:

• Users experience delays during logon and logoff. These delays could be anywhere between 10 seconds and 10 minutes, or even more.
• This issue could occur when the DEM config and/or profile SMB shares are hosted on EMC filers with the 'Oplocks' feature enabled.

Environment

VMware User Environment Manager 9.x

Cause

• Oplocks allow a client to notify the file server that it will not only be the exclusive writer of a file but will also cache its changes to that file locally to speed up file access.
• When the file server identifies that a file has been opportunistically locked by a client, it marks its version with an opportunistic lock and waits for the client to complete work on the file.

An example of a UEM logfile that shows delays during logon can be found below:
 

2018-05-29 10:33:04.015 [INFO ] Config file '\\EMC_Isilon\UEM_CONFIG\General\Applications\Notepad++.ini' added to DirectFlex cache
2018-05-29 10:33:14.031 [INFO ] Config file '\\EMC_Isilon\UEM_CONFIG\General\Applications\Notepad.INI' added to DirectFlex cache
2018-05-29 10:33:24.019 [INFO ] Config file '\\EMC_Isilon\UEM_CONFIG\General\Applications\Paint.INI' added to DirectFlex cache
2018-05-29 10:33:34.015 [INFO ] Config file '\\EMC_Isilon\UEM_CONFIG\General\Applications\PaintDotNet.ini' added to DirectFlex cache
2018-05-29 10:33:44.004 [INFO ] Config file '\\EMC_Isilon\UEM_CONFIG\General\Applications\Edit.INI' added to DirectFlex cache
2018-05-29 10:33:54.008 [INFO ] No profile archive to import for config file '\\EMC_Isilon\UEM_CONFIG\General\Applications\PuTTy.INI'

When you experience this issue you would typically see delays between processing of each file (as you can see the 10-second delay between each file process in the example above).

Resolution

Oplocks provides performance improvements on SMB 1.0 and 2.0.
With SMB 2.1, Microsoft introduced 'Leases' as a replacement for Oplocks. When possible, configure the EMC filers to offer SMB 2.1 or newer shares.

Workaround:
When the resolution above is not possible, a workaround is to disable SMB Oplocks.

Impact of workaround: This command disables Oplocks on the entire volume; therefore, no clients can use Oplocks on files.

Additional Information

Disclaimer: VMware is not responsible for the reliability of any data, opinions, advice or statements made on third-party websites.

More information about SMB Oplocks can be found here:
Client caching features: Oplock vs. Lease