Error alerts from the DNS MP – script failures, WMI Probe failed?

re: Error alerts from the DNS MP – script failures, WMI Probe failed?

Marnix Wolf — Tue, 30 Jun 2009 10:11:12 GMT

Hello Kevin.

Many times the solutions you describe work perfectly. However, on many occassions I find that for the DNS MP the updates of WMI and Windows Scripting Host is not sufficient. The DNS class in WMI has to be recompiled as well.

Then all errors are gone and everything runs like clockwork again.

So on DNS servers I start three actions:

- Updating WMI

- Updating Windows Scripting Host

- Recompiling DNS class in WMI

re: recompile DNS mof?

kevinhol — Tue, 30 Jun 2009 16:35:25 GMT

Here is the only problem I have with recompiling the MOF: In my testing - recompiling the MOF is only necessary when the DNS WMI namespace is missing or corrupt. If after bouncing the WMI service, you still cannot manually query any of the WMI objects, or cannot even connect to the WMI namespace, then I agree - recomplile the mof.

However - in my testing - I did all three - updated WMI, recompliled MOF, and then updated cscript. After 1 month passed - the issue returned. It seems to take a long amount of uptime for this random error condition to present itself. That is why I am adding the additional WMI buffer space now. This supposedly will address the issue for most people. I will let you know in a month or two. :-)

re: Error alerts from the DNS MP – script failures, WMI Probe failed?

Marnix Wolf — Tue, 30 Jun 2009 21:12:58 GMT

Oops. So even with recompiling the MOF the issue returns...

Good to know about adding additional WMI buffer space. If that solves this problem also on the long term it is good to know.

Thanks again for sharing such good information with the community.

re: Error alerts from the DNS MP – script failures, WMI Probe failed?

number33 — Wed, 12 Aug 2009 17:00:24 GMT

Hi Kevin,

I'm afraid it does not help.

We recompiled the DNS mof, installed KB933061, increased teh buffer space, finally rebooted the systems.

It was a relief for some time, but the errors reappeared after some time.

I'm afraid there is something wrong with either WMI or DNS mof or both ?

re: Yep

kevinhol — Wed, 12 Aug 2009 17:12:16 GMT

Yep... totally agree. I am seeing the same now.

The current theory, is that something is wrong with the WMI provider for DNS.... this isnt related to SCOM. That issue is - that this DNS WMI provider leaks a TLS slot and when they are exhausted (takes about 2-3 weeks for me) then the problem occurs.... When this happens, you can bounce WMI/Reboot the computer, and the problem goes away for 2-3 weeks.

The provider unloads after 5 minutes of inactivity. If you did something - say.... run a times script that does something VERY lightweight, like runs the simple WMI query and nothing else - against the DNS WMI namespace, and run this script every 2 minutes. This would keep the provider from loading/unloading as caused by the SCOM MP.... and the TLS slots will not leak because the DNS provider is not unloading. I was also thinking of maybe writing a threshold monitor - against a WMI perf object, that wont change/alert... and this might keep the provider loaded and have even less impact.

That is a theory, I have not had time to test and validate this.