Dell ThinOS 9 and 10 Slow Login on Horizon VDI Session

Affected Operating Systems:

• Dell ThinOS 10 2502
• Dell ThinOS 9 2402 and Later

After deploying on ThinOS, the Horizon Client SDK package time to log in to a published host pool increases from less than two seconds to six to eight seconds.

• The issue is not in ThinOS 2402 and VMware_Horizon_2309.8.11.0.22660930.37.pkg (Horizon Session SDK package)
• The issue is not in ThinOS 2402 and VMware_Horizon_2306.8.10.0.21964631.3.pkg (Horizon Session SDK package)
• The issue is more noticeable on low specification devices.

• The issue has been introduced with the Horizon Client SDK package:
  • During the initialization of the connectivity to the remote Horizon session, a key pair must be generated on the Thin Client.
  • This is a complex mathematical computation with high CPU usage.
  • This function is part of the Horizon Client SDK and does not leverage hardware acceleration.
• This issue is not present in the Horizon Session SDK package.
• Checking the ThinOS logs at the time of the issue that it is possible to see something similar to the below related to the key pair generation process:

  compat/linux/var/log/wlogd/
              [TIMESTAMP1] D/vmware-view /vmware-view (yyyy/yyyy) [All] CdkUtil_GenerateDHKeyPair:xxxx: Entry
              [TIMESTAMP2] D/vmware-view /vmware-view (yyyy/yyyy) [All] CdkUtil_GenerateDHKeyPair:xxxx: Exit
              

The time difference between the two timestamps is four to six seconds.

The issue has been resolved in ThinOS 9 2505 and in ThinOS 10 2502.60 Firmware Upgrade Package.

Workaround:

Do one of the following:

• Downgrade the ThinOS 9 to a working version such as the below ones:
  • ThinOS 2402 and VMware_Horizon_2306.8.10.0.21964631.3.pkg
  • ThinOS 2402 and VMware_Horizon_2309.8.11.0.22660930.37.pkg
• Enable the FIPS authentication compliance in the ThinOS policies. This forces a more efficient algorithm for the key pair generation.
  Note: To enable it, from the Wyse Management Suite (WMS) console, edit the relevant ThinOS policy for the affected device group and go to Advanced > Privacy & Security > Device Security > Device Security > Enable FIPS
  

Some additional prerequisites may be necessary in your environment to successfully use FIPS authentication.