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SBS 2011 Memory-Related Bottlenecks RRS feed

  • Question

  • In a search to solve slow network throughput, I stumbled across this page http://mscerts.programming4.us/windows_server/Windows%20Server%202008%20%20%20Monitoring%20System%20Performance%20(part%201)%20-%20Key%20Elements%20to%20Monitor%20for%20Bottlenecks.aspx

    Under 'Monitoring System Memory and Pagefile Usage' it advices which performace counters to check for memory-related problems. So I did. And the numbers I read on my SBS server suggest big problems. Most important counter is "Pages/sec". If this numer is consistently higher than 20, there's a problem. On my system, I read an average of 230, and when a large file is copied from server to client, it climbs to an average above 10000.

    So I did some more searching and came across http://technet.microsoft.com/en-us/magazine/dd722744.aspx. This article says I have to check out (among others) 'Memory\Available Mbytes' and 'Memory\Committed Bytes'. The committed bytes value should be no more than 75 percent of the total physical memory. When I check this number on my server, it reads 1.8487e+010. Or 18487000000 bytes / 17.2 GB. The server has 16 GB of memory, so this figure is a lot higher as 75%. The recommendation for both situations: add more RAM.

    But what I don't understand is this. When I run Task Manager and take a look at the performace tab, I read a total memory of 16367, cached memory 8980, available memory 8940 and fee memory 0. Kernel memory paged 333, nonpaged 198. When I look at those figures, I conclude about half the memory is free?

    So why do the figures of the perfomance counter indicate I have to add more RAM, but do the figures on the taskmanager performance tab indicate the opposite (i.e. plenty of RAM available)?

    Simon

    Wednesday, November 23, 2011 3:04 PM

Answers

  • How long was the server running before you checked the values?  Both Exchange and SQL will slurp up all available RAM as they run to optimize things but it takes a few days to stabilize.  The idea here is their is no use for "free" ram on a server.  Both Exchange and SQL supposedly will free memory as needed for other processes although some tune SQL to limit how much it takes based on their application.
     
    Usually more RAM is better of course but it depends upon the number of active users and the server load.

    --
    Allan Williams
     

     

    In a search to solve slow network throughput, I stumbled across this page http://mscerts.programming4.us/windows_server/Windows%20Server%202008%20%20%20Monitoring%20System%20Performance%20(part%201)%20-%20Key%20Elements%20to%20Monitor%20for%20Bottlenecks.aspx

    Under 'Monitoring System Memory and Pagefile Usage' it advices which performace counters to check for memory-related problems. So I did. And the numbers I read on my SBS server suggest big problems. Most important counter is "Pages/sec". If this numer is consistently higher than 20, there's a problem. On my system, I read an average of 230, and when a large file is copied from server to client, it climbs to an average above 10000.

    So I did some more searching and came across http://technet.microsoft.com/en-us/magazine/dd722744.aspx. This article says I have to check out (among others) 'Memory\Available Mbytes' and 'Memory\Committed Bytes'. The committed bytes value should be no more than 75 percent of the total physical memory. When I check this number on my server, it reads 1.8487e+010. Or 18487000000 bytes / 17.2 GB. The server has 16 GB of memory, so this figure is a lot higher as 75%. The recommendation for both situations: add more RAM.

    But what I don't understand is this. When I run Task Manager and take a look at the performace tab, I read a total memory of 16367, cached memory 8980, available memory 8940 and fee memory 0. Kernel memory paged 333, nonpaged 198. When I look at those figures, I conclude about half the memory is free?

    So why do the figures of the perfomance counter indicate I have to add more RAM, but do the figures on the taskmanager performance tab indicate the opposite (i.e. plenty of RAM available)?

    Simon

    Thursday, November 24, 2011 6:19 PM