We have struggled for some time with random black screens when users log into an instant clone session since moving to Horizon 8. Horizon 8 moving away from the SVGA driver has been the issue for us and support has had us install the 2106 agent to the master images (though connect servers are at a higher level) as it was the last version that still installed the SVGA driver. That mostly solved our problem. I just upgraded our connection servers to 2212 and the agent on the images was still 2106 and now the black screen issue has returned. This is not the black screen where the user gets disconnected after a few seconds, related to video memory, The user will stay connected as long as they desire to wait but the session is black and they can't do anything. I have just deployed new instant clone pools with the 2212 agent installed but also allowed the Tools install to push the SVGA driver and yes, I followed the install order of Tools, then the Agent. I have yet to see if this will correct the issue. The only other variable on the old images was a growing number of snapshots. I get conflicting information from each support engineer I talk to. Several times I have been told to not have more than 2 snapshots on the master image but removing earlier snapshots makes Horizon complain about missing snapshots. I have had yet other engineers tell me that yes, do not remove snapshots from a master image. What is the "best practice" regarding the number of snapshots on a master image and can a larger number cause performance issues on an instant clone pool? Should a master image be cloned first if additional snapshots are required after reaching a recommended limit?
If the master VM of the instant clone has many snapshots, the image push of the instant clone will take longer.
A slow image push will result in a timeout, so in this regard, it is not a mistake to say that Horizon's performance will be degraded if there are many snapshots.
However, I believe that the black screen is caused by the Horizon Agent's video driver (SVGA , Indirect display driver).
Also, to examine the black screen event in detail, it would be useful to implement method2 of KB2078739.
VMware Horizon and VMware Tools SVGA Driver Compatibility. (2078739)
Additionally, if you are using PCoIP, you should check if the same problem occurs with VMware Blast.
It seems to me that maybe VMware Blast would not cause the problem.
The number of snapshots on master VM will not cause any issues on the instant clones. However, it's better to keep minimum number of snapshots in order to keep the master VM clean and also to reduce the VM size. The error about missing snapshot can be ignored and it won't cause any issues during pool creation or maintenance.
What happens when you roll-back to the previous version?
I used version 2111 and it works perfectly fine.
Consider this VMware Horizon 8 version 2212 documentation for known issues.
I upgraded from 2111 and have not tried to roll back. It is a little difficult for me to schedule for any possible downtime as we are a 24/7/365 hospital facility and the bulk of our VM environment is used in direct patient care. Also makes me very cautious about making any changes. I had the same issue with 2111 until support told me to install the 2106 agent which is the last version of the agent that still installs the SVGA driver. In regards to the other post, I agree about the SVGA driver being the issue but since I am on a version of Horizon that is beyond having the SVGA driver bundled with the agent, the solutions of not installing the Tools SVGA don't work as then there is no SVGA driver installed. Thank you all for the input, I'm hoping VMware support can finally find something in the logs to identify why I seem to be the only one having such an issue.
Try the following registry in the master VM of the instant clone
HKLM\Software\Policies\VMware, Inc.\VMware Blast\config
REG_SZ : 1
After that, expand to a new one.
Are there any changes?
The registry is set to use the VMware Indirect display driver for screen rendering instead of using the SVGA driver.
I generally draft a SR for VMware when I get a black screen.
Also, everyone is still installing the SVGA driver from VMware Tools and not using IDD (VMware Indirect Display Driver), which is why the event occurs, so I tentatively addressed it in the registry and it was cured.
I then uninstalled VMware Tools and installed the Horizon Agent, being careful not to install SVGA.
Now I am able to operate without the registry without any problems.