Sql-server – Does WMI cause CPU Creep

cpu-usagesql serverwindows-server-2003wmi

I have a few servers, running Server 2003 Std/Ent and SQL 2000/2005, that I've noticed will start showing higher CPU usages over time. Stopping the WMI service and restarting it will always bring it back down. It's not a huge creep, but after a month it will be around a 10% increase, so even in idle times, it will show 10% cpu usage. We don't use WMI heavily, just a couple of scripts checking service states, and perfmons (does it use WMI?) which is how it was noticed. Are there WMI trace tools? Any other methods to troubleshoot this? The servers that show the symptoms are vastly different, no common elements other than the OS and SQL.

Best Answer

I actually had this problem once. We pulled up filemon and found that WMI was writing to a log file a lot (Framework.log). We checked out the file and found it grew over 2 GB in size. We either renamed the file or stopped the service and renamed it (can't remember). At any rate, we found that it relieved the CPU. There is a KB article with a fix published that shows why the file gets so large and how to fix it. This worked for us:

http://support.microsoft.com/kb/836605

HTH

Related Solutions

Sql-server – Need a resource that lists WMI perfmon classes

You can use PowerShell to list classes in a namespace.

get-wmiobject -list

will list all classes in the default ("\root\cmiv2") namespace, the -namespace parameter can be used to specify a different namespace.

To get all the performance classes, use either:

get-wmiobject -list | ?{$_.Name -like 'Win32_PerfRaw*'}

for raw data, or:

get-wmiobject -list | ?{$_.Name -like 'Win32_PerfForm*'}

for formmater data. Perfmon shows formatted data (processed by counter type), raw is what the performance counter provider is sending without any further processing.

Getting error “WMI: Not Found” on a Windows 2003 Server

The following script can be run to rebuild a corrupt WMI
(Source: Duncan McAlynn, 2004-11-22, How Do I Rebuilt a Corrupt WMI Repository?) _{(Dead link. Archived version here.)}

net stop winmgmt
c: 
cd %systemroot%\system32\wbem 
rd /S /Q repository 


regsvr32 /s %systemroot%\system32\scecli.dll 
regsvr32 /s %systemroot%\system32\userenv.dll 


mofcomp cimwin32.mof 
mofcomp cimwin32.mfl 
mofcomp rsop.mof 
mofcomp rsop.mfl 
for /f %%s in ('dir /b /s *.dll') do regsvr32 /s %%s 
for /f %%s in ('dir /b *.mof') do mofcomp %%s 
for /f %%s in ('dir /b *.mfl') do mofcomp %%s 
echo DONE reboot 
pause

Best Answer

Related Solutions

Sql-server – Need a resource that lists WMI perfmon classes

Getting error “WMI: Not Found” on a Windows 2003 Server

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