AWE Memory

  • Hello,

    We are running an SQL2008R2 32-bit instance on a Win2003R2 64-bit OS with 8GB.

    When we enable AWE and set the 'Maximum Server Memory' to 7000 we get strange results:

    - After rebooting only 5.7 GB is reserved for SQL-Server.

    - After restarting the SQL-Server there is also only 5.7 GB reserved for SQL-Server.

    The only way to get more memory for SQL-Server is by:

    - Setting the 'Maximum Server Memory' to e.g. 3500,

    - restart SQL-Server,

    - and finally increase the 'Maximum Server Memory' from 3500 to e.g. 7000.

    This way we can reserve 7 GB for SQL Server.

    But after restarting the reserved amount is dropped again to 5.7 GB

    Anyone an idea for this strange behaviour after rebooting/restarting?

    Thx!!

    Geert

  • have you given the service account the lock pages in memory right?

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  • george sibbald (10/19/2010)


    have you given the service account the lock pages in memory right?

    Yes, I think otherwise the memory will be limited to 2 GB

  • the max value is dynamic for SQL2005 and above. Is something else grabbing the memory? does it increase to 7GB of its own accord over time?

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  • george sibbald (10/19/2010)


    the max value is dynamic for SQL2005 and above. Is something else grabbing the memory? does it increase to 7GB of its own accord over time?

    I think not because after restarting SQLServer (with the max. mem. at 3500) I can manually increase the max. mem,. to 7000, and then the Target Server Memory in PerfMon raises to 7GB. After restarting SQLServer with max. mem. at 7000 the it stays forever on 5.7 GB

  • gn 418 (10/19/2010)


    Hello,

    We are running an SQL2008R2 32-bit instance on a Win2003R2 64-bit OS with 8GB.

    AWE cannot be configured is not needed if you are running on a 64-bit Operating System:

    http://msdn.microsoft.com/en-us/library/ms190731.aspx

    Shawn Melton
    Twitter: @wsmelton
    Blog: wsmelton.github.com
    Github: wsmelton

  • It is not needed for SQL 64-bit, but is needed (I think) for SQL 32-bit on a 64-bit OS, since SQL 32-bit runs under WOW64....

  • If you go by the definition of what the AWE setting is for, you don't need it due to the 64-bit OS you are running. You also will find that this setting is going to be removed from SQL Server future releases:

    http://technet.microsoft.com/en-us/library/ms190673.aspx

    Shawn Melton
    Twitter: @wsmelton
    Blog: wsmelton.github.com
    Github: wsmelton

  • SQL Server is running on 32-bit subsystem (WOW64). WOW64 is a feature of 64-bit editions of Microsoft Windows that allows 32-bit applications to execute natively in 32-bit mode. Applications function in 32-bit mode even though the underlying operating system is running on the 64-bit platform. So the SQL Server can't use more than 4 GB memory (32-bit OS support no more than 4 GB).

    That's why I think AWE is necessary.

  • Why don't you just run the 64-bit version of SQL Server?

    Shawn Melton
    Twitter: @wsmelton
    Blog: wsmelton.github.com
    Github: wsmelton

  • We are upgrading from SQL2K and our customer is using some functionality not available in de x64 version: JET-drivers, DTS, and some COM-objects to interface with other applications, ...

  • How much RAM is in the server? Have you added the /3GB switch in the boot.ini file?

  • nevhirion (10/21/2010)


    How much RAM is in the server? Have you added the /3GB switch in the boot.ini file?

    There is 8GB in the server, it's 64-bit so /3GB is not applicable I suppose

  • You really need to check this link...

    http://www.mydigitallife.info/2008/06/07/optimize-sql-server-2000-2005-or-2008-in-large-ram-system-by-locking-pages-in-memory-and-awe/

    i will post the other link which msdn says about the levels of AWE and PAE in sql sevre supports and needs to be activated.

    @JayMunnangi

  • My problem is not that it is not working, I can use > 7GB (from the 8GB in the box).

    But after rebooting or restarting SQL Server I suddenly can only use 5.7GB !!

    After manipulating the AWE-settings I can use again 7GB. After rebooting/restarting the max is dropped again to 5.7GB.

    See details in my first post at the start of this thread...

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