Memory Management - awe /3gb /pae

  •  I have the following setup -

    Server 1: Windows 2003 Enterprise Edition; SQL 2000 Standard Edition; Memory = 4 Gig

    Server 2: Windows 2003 Enterprise Edition; SQL 2000 Enterprise Edition; Memory = 8 Gig

    Awe has never been enabled ..or max server memory set..etc..

    I was curious if the following was the best way to configure the memory:

    Server 1: enable /3gb switch in boot.ini  (This gives sql 3 gig and leave 1 gig for OS correct??); DO NOT ENABLE Awe since awe is for servers with more than 4 gig of memory.

    Server 2: enable /3gb /Pae switch in the boot.ini  enable awe  and set the max server memory to 6 gig (would this mean sql would get 6 gig and leave 2 for the OS??)

    Would the above memory configuration be correct?

    Thanks!


    Kindest Regards,

    JWA

  • You seemed to have summarised it well! Just remember to set both the minimum and maximum server memory. Your setting of 6GB for the second server could be upped a notch to 7GB, unless the server will host other application services which requires considerable memory. Finally, check that you have configure the memory correctly using PerfMon and select SQLServer:MemoryManager-->TotalServerMemory.

  • You didn't mention whether you were using the 32 bit or 64 bit version of Win2003 Server.  With the 64 bit you don't need to mess with the switches at all.

     


    Student of SQL and Golf, Master of Neither

  • Whoops, my bad.  You are using SQL 2000, we're on 2005.  My comment probably doesn't apply.

     


    Student of SQL and Golf, Master of Neither

  • SQL Server 2000 Standard Edition is limited to 2 GB, regardless of the OS or machine memory capacity. Refer to BOL "specifications-SQL Server objects"

  • I have an additional question on this topic. What versions of Windows 2000 will let you enable the 3gb switch? I found this on the Microsoft website:

    /3GB

    With this switch, user mode programs can access 3 GB of memory instead of the usual 2 GB that Windows allocates to user mode programs. The switch moves the starting point of kernel memory to 3 GB. This switch is used only with Windows 2000 Server Enterprise Edition.

    But then I find another paper that tells me SQL Server 2000 can run on these operating systems:

    • Windows® 2000 Server

    • Windows 2000 Advanced Server

    • Windows 2000 Datacenter Server

    So which one of these is Windows 2000 Enterprise Edition?

    An attempt was made to enable the 3gb swith on one of our servers and a serious problem was encountered; I'm trying to get the exact error message from one of our other DBAs. I apologize for not posting it here. We are currently running Windows 2000 5.00.2195 Service Pack 4.

    Thanks for the help.

    Mark

  • Thank you all for your replies. I appreciate it!

    So if I am reading it all correctly:

    Server 1: Windows 2003 Enterprise Edition; SQL 2000 Standard Edition; Memory = 4 Gig - I should not enable /3gb switch in boot ini since sql can only take hold of 2 gig???

    Server 2: enable /3gb /Pae switch in the boot.ini enable awe and set the max server memory to 7 gig

    Thanks!


    Kindest Regards,

    JWA

  • Also - one more clarification if I may..

    In sp_configure..what would I set the min server memory to if i set the max server memory to 7 gig?

    Thanks!


    Kindest Regards,

    JWA

  • For a listing of the different flavours of Windows OS and SQL Server editions, and whether or not AWE is supported, have a look at this article:

    http://www.sql-server-performance.com/awe_memory.asp

    Another thing to consider (also from the article) is this statement:

    '...your goal of using AWE memory should be to support a single, very large instance of SQL Server, not lots of smaller instances running on a single server'

    As to the minimum server memory setting, a value of 0.5GB would suffice.

  • I just saw this thread and am now semi confused.

    I too have a Windows 2003 (32bit) server running standard edition of SQL 2000 with 4GB of RAM on the machine.

    I see one person saying to use the AWE switch to enable the machine to utilize the extra memory (which I erroneously believed it did inherently).  Is this correct?

    Or do I leave things as they are due to the risk of causing an error by enabling AWE?

  • AWE allows access to memory OVER 4GB (4GB is the maximum amount of memory addressable with a 32-bit memory address). If you have a 4GB server, don't use AWE.  Next is /3GB, which tells Windows to use 1GB for the OS and allows 3GB for applications. However, since you are using SQL2K Standard Edition, only 2 GB is usable, so there is no reason to use /3GB either.

     

     

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