/3GB Switch

  • There is one requirement that I have to edit boot.ini file and make /3GB switch on in Vista:doze:. I am not able to do that. I am a sql server DBA and I used to do this when I used to use win2000 and XP.

    -MJ

    -MJ
    Please do not print mails and docx unless it is absolutely necessary. Spread environmental awareness.

  • MichaelJasson (6/30/2009)


    There is one requirement that I have to edit boot.ini file and make /3GB switch on in Vista:doze:.

    Why do you want to do that?

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • I wouldn't think you would want to do that on Vista. If you are running on x86 hardware, then the maximum memory you are going to be able to address is 3GB. Setting that switch won't leave any memory to the OS.

    If you are running x64 - that switch won't do anything anyways.

    So, I'm with Gail on this one - why do you want to do this?

    Jeffrey Williams
    “We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”

    ― Charles R. Swindoll

    How to post questions to get better answers faster
    Managing Transaction Logs

  • try BCDEdit.exe or Bootmgr.exe

    Abhay Chaudhary
    Sr.DBA (MCITP/MCTS :SQL Server 2005/2008 ,OCP 9i)

  • Thanks for your response SSCrazy and Gail.

    The reason I want to do that is that my application is running very slow. I want to allocate more memory to sql server because page reads/sec and page writes/sec are really havoc.

    /3GB would help me allocating one GB more to sql server and would help increasing the cache/Buffer by 1 GB.

    I think Cache and Buffer are same thing. Correct me if I am wrong.

    -MJ

    -MJ
    Please do not print mails and docx unless it is absolutely necessary. Spread environmental awareness.

  • Cache is inside the buffer Pool ..its a subset .

    Abhay Chaudhary
    Sr.DBA (MCITP/MCTS :SQL Server 2005/2008 ,OCP 9i)

  • MichaelJasson (7/2/2009)


    The reason I want to do that is that my application is running very slow. I want to allocate more memory to sql server because page reads/sec and page writes/sec are really havoc.

    But we're talking a client OS. Doing this on a server that's dedicated to SQL is one thing, doing it on a client OS (especially one as memory-hungry as Vista) is something completely different.

    Where is the SQL server that your app is using? One the Vista machine? If so, I recommend you move it to a proper server environment.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • Thanks. Following link defines well about buffer pool and cache. Should I use the files you gave me to enable /3GB switch. Can you give me any link which tells me that I can use them as I am going to do this on a production server.

    -MJ
    Please do not print mails and docx unless it is absolutely necessary. Spread environmental awareness.

  • MichaelJasson (7/2/2009)


    Can you give me any link which tells me that I can use them as I am going to do this on a production server.

    A production server running Vista? You sure?

    Before you add anything, can you maybe give some more info as to exact OS version, SQL server, amount of memory in the server and 32 bit or 64 bit?

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • Yes this is on Vista. My TL took a decision to have this on Vista and not Microsoft sql server 2008 which we proposed. I was not able to convince him with facts. Do you have any doc which informs me that this should not be on Vista.

    My sql server version is as follows:

    Microsoft SQL Server 2008 (SP1) - 10.0.2714.0 (X64) May 14 2009 16:08:52 Copyright (c) 1988-2008 Microsoft Corporation Enterprise Edition (64-bit) on Windows NT 6.0 (Build 6002: Service Pack 2) (VM)

    I used DBCC MEMORYSTATUS and found many results. Out of which following gives enough information:

    Available Physical Memory342089728

    Available Virtual Memory844

    Available Paging File234

    Working Set133296128

    Percent of Committed Memory in WS100

    Page Faults5060377223231

    System physical memory high1

    System physical memory low0

    Process physical memory low0

    Process virtual memory low0

    -MJ
    Please do not print mails and docx unless it is absolutely necessary. Spread environmental awareness.

  • MichaelJasson (7/2/2009)


    Thanks for your response SSCrazy and Gail.

    The reason I want to do that is that my application is running very slow. I want to allocate more memory to sql server because page reads/sec and page writes/sec are really havoc.

    /3GB would help me allocating one GB more to sql server and would help increasing the cache/Buffer by 1 GB.

    I think Cache and Buffer are same thing. Correct me if I am wrong.

    -MJ

    You should give us more information regarding your environment as how much your memory is? what are the min and max memory settings on your SQL server. is it 32-bit or 64 bit? and also the reason that you want to switch on the /3GB? then we would be abel to give you a clearer idea.

  • MichaelJasson (7/2/2009)


    Yes this is on Vista. My TL took a decision to have this on Vista and not Microsoft sql server 2008 which we proposed. I was not able to convince him with facts. Do you have any doc which informs me that this should not be on Vista.

    Vista is a client operating system. It's for workstation machines, not servers. It's neither designed nor optimised for server apps. That you're running Vista instead of a server OS is very likely a major cause of memory problems. Vista is a memory hog and it uses a lot of resources to look good for the user.

    Microsoft SQL Server 2008 (SP1) - 10.0.2714.0 (X64) May 14 2009 16:08:52

    There's no point in you adding the /3GB switch. It will have no effect since both the OS and SQL are 64 bit. /3GB is only used on 32 bit operating systems to allow apps to access 3GB of memory instead of 2GB.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • Thanks Gila for great info.

    And this is not the only server we are using. There is one more server which is as follows:

    Microsoft SQL Server 2000 - 8.00.2055 (Intel X86) Dec 16 2008 19:46:53 Copyright (c) 1988-2003 Microsoft Corporation Enterprise Edition on Windows NT 5.2 (Build 3790: Service Pack 2)

    And DBCC Memorystats give following information:

    Stolen1412

    Free16

    Procedures6884

    Inram0

    Dirty9236747

    Kept0

    I/O0

    Latched64

    Other182

    -MJ
    Please do not print mails and docx unless it is absolutely necessary. Spread environmental awareness.

  • Is there a question there?

    If you want advice on memory settings, you're going to specify the hardware in that server. Just seeing DBCC memory status alone says very little.

    Gail Shaw
    Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
    SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability

    We walk in the dark places no others will enter
    We stand on the bridge and no one may pass
  • MichaelJasson (7/2/2009)


    Microsoft SQL Server 2000 - 8.00.2055 (Intel X86) Dec 16 2008 19:46:53 Copyright (c) 1988-2003 Microsoft Corporation Enterprise Edition on Windows NT 5.2 (Build 3790: Service Pack 2)

    You are not running Windows Vista on your server. You are, in fact, running Windows Server 2003 Enterprise Edition SP2. This is also running on x64 hardware so you don't have to worry about setting /3GB, /PAE or AWE.

    From what I have been able to see - it looks like your server has 32GB of memory. If you have not set a max of no more than 28GB of memory, your system is going to have problems. Is this a dedicated database server, or is it running other applications? If it is running other applications it is even more important that you set max memory.

    Jeffrey Williams
    “We are all faced with a series of great opportunities brilliantly disguised as impossible situations.”

    ― Charles R. Swindoll

    How to post questions to get better answers faster
    Managing Transaction Logs

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