Corrupt WMI Repository

[Darryl Sakach]

I have a case open with support for Network Session Metrics not being returned to Monitor or CQI. This is for LTSR 2203 CU1 VDA. They have asked me to rebuild the WMI performance counters per CTX310681. This is an App Layered (2208) image so my question to them was what layer they want me to perform this in. Surprisingly their answer was just trying each layer (platform and OS) to see which one works.

 

Does anyone have any guidance on rebuilding perf counters in App Layering?

[Rob Zylowski]

Any WMI changes should be in the platform layer but I would try just creating a new one.

 

But its also important to know that any WMI schema changes have to go in the platform layer.  We do not merge WMI schema updates and since the VDA modifies the WMI schema you should put any apps that also modify the WMI schema in the platform layer or the Platform Layer will write over any of those changes.  This does not means apps that use WMI only ones that modify it.

[Darryl Sakach]

Thanks Rob.

 

We originally had more perf counters that were not being returned. Support had us update the ELM and rebuild the layer citing an issue that was fixed in layering that would resolve the issue. That did resolve many of the missing counters, but not the Networking counters for ICA Latency, Protocol and HDX Network stats. 

 

I will try the rebuild in the Platform Layer. If that does not work, I will rebuild the layer altogether once more.

 

How would an admin know if the software modifies the WMI schema?

[Rob Zylowski]

If it adds new counters

[Darryl Sakach]

Wow, that could be big. So that I am sure I understand, any software that adds new perf counters should be installed in the Platform Layer. This is because you do not merge WMI schema changes from other layers, the only layer where those changes will persist is the Platform Layer.

 

[Rob Zylowski]

Yes WMI is a flat database ie a file.  So if you make changes to that file in any layer one layer writes over another based on priority.  Since the platform alyer has the highest priority in the image and we know the WMI schema gets changed there it will always overwrite that file in any other layer,

 

But not many applications add counters to WMI.

[Darryl Sakach]

Thinking about this further, I expect there are many Perf Counters in the OS Layer. Would this mean each time we update the OS Layer we should then update the Platform Layer to ensure it picks up any new or updated perf counters?

[Rob Zylowski]

I doubt hey change much but whenever you do a feature update if its win10/11 you should create a new platform layer.