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I am collecting PerfMon counters on a SQL Server 2008 server (which is hosted on a VM), and I am getting different Page File % Usage values for _Total and C:\pagefile.sys. The C:\pagefile.sys values are consistently at zero, and the _Total values are consistently around 26. Other counters (Memory Grants Pending, Page Life Expectancy, Processor Queue Length, Available MBytes) all are showing values indicative of memory and cpu pressure, so I would think that there would be some indication of paging to disk (which the _Total pagefile usage value agrees with but the C:\pagefile.sys instance value does not).

Would anyone have insight into how I should evaluate these two Pagefile % Usage values to determine the actual pagefile usage on the server? Does the fact that the Server is a Virtual Machine have anything to do with why there are two values?

MDMarra
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caljerm
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1 Answers1

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Would anyone have insight into how I should evaluate these two Pagefile % Usage values to determine the actual pagefile usage on the server?

There are a few things that can be happening here, I'll list them in order of likelihood:

  1. You don't have a pagefile at C:\pagefile.sys. It's incredibly rare for there to be absolutely zero usage. You can check the location of your pagefile(s) by running wmic pagefile /format from an elevated command prompt.

  2. You have more than one pagefile and the one on c:\ just isn't getting any use. Still pretty uncommon but possible. Run the command above to verify.

  3. You're reading the Perfmon graph incorrectly. Pretty unlikely, since it's straight forward, but worth mentioning since you didn't post a screenshot of it.

Does the fact that the Server is a Virtual Machine have anything to do with why there are two values?

No.

MDMarra
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  • thanks for the feedback. I guess I hadn't mentioned that I was collecting the counters to .csv - when I switched over to binary and viewed the graph, it just showed one line for swap file, and it agreed with the _Total counter value (around 26%). So I guess that perfmon knows graphically to ignore that non-useful counter instance, but lets you select it when putting together your collector set. I did run wmic pagefile list /format:list and it showed the pagefile as C:\pagefile.sys with allocated size of 2048 and current usage of 532 - which just happens to come out to 25.97% – caljerm Oct 03 '12 at 13:46