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AWE

  • July 23, 2010 at 1:00 pm

    #387416

    Hi,

    32-bit Windows system can only access 4GB of memory. But what exactly does this mean?

    Thanks in Advance.

  • July 23, 2010 at 1:20 pm

    #1197720

    This is official documentation of AWE

    Pradeep Adiga
    Blog: sqldbadiaries.com
    Twitter: @pradeepadiga

  • July 23, 2010 at 2:39 pm

    #1197774

    Adiga (7/23/2010)

    This is official documentation of AWE

    Thanks for your reply, but can you let me know answer for my previous question ?

  • July 27, 2010 at 3:20 am

    #1198597

    Double post

  • July 27, 2010 at 3:22 am

    #1198600

    Win 32bit STANDARD can only use 4Gb RAM maximum. To use more than this you would need to install Enterprise Edition.

    To allow SQL Server to access this extra memory available in Windows, you need to configure the OS to use AWE memory.

  • July 27, 2010 at 4:37 am

    #1198623

    There is another side to this.

    If you are running a 32bit OS, you'll need to make use of the PAE switch in the Boot.INI as well, to allocate more than 4GB of memory, and the the AWE to allocate memory from that.

    You'll also need to set a min and max memory size for SQL Server, and Lock pages in Memory.

    Read up on the link provided, and make sure you know what you are enabling.

    -----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
    This thing is addressing problems that dont exist. Its solution-ism at its worst. We are dumbing down machines that are inherently superior. - Gilfoyle

  • July 27, 2010 at 11:09 am

    #1198852

    Hi Sudhakara,

    32-bit Windows system can only access 4GB of memory. But what exactly does this mean?

    32-Bit windows can access only upto 4 GB of memory. If you need to make the windows server to access more than 4GB of RAM you need to enable PAE switch.

    For the SQL Server to use the physical memory added in additional to the actual 4GB on the Box, AWE has to be enabled.

    For SQL server to use upto 3GB RAM, use /3GB switch.

    For SQL server to use upto 4GB RAM, use AWE along with /PAE switch.

    This rule of thumb may help you,

    If the Memory Avaible on the Box is

    <4GB Don't use any special setting

    = 4GB Use /3GB switch

    >4GB Use /PAE switch along with AWE

    AWE is not required on 64-bit systems.

    Min and Max Memory settings along with Lock pages in Memory privilege is recommended on both 32 bit and 64 bit SQL Servers to get optimum SQL Server performance

    Thank You,

    Best Regards,

    SQLBuddy.

  • July 28, 2010 at 12:25 am

    #1199079

    smackie1973 (7/27/2010)

    Win 32bit STANDARD can only use 4Gb RAM maximum. To use more than this you would need to install Enterprise Edition.

    To allow SQL Server to access this extra memory available in Windows, you need to configure the OS to use AWE memory.

    Thanks for your reply. I too knew that windows 32 bit system can access only 4 GB of memory.But i dont know why only 4 GB can able to access even if i have 6 GB of RAM in my system.

  • July 28, 2010 at 2:11 am

    #1199107

    sudhakara (7/28/2010)

    But i dont know why only 4 GB can able to access even if i have 6 GB of RAM in my system.

    You might find the answer here.

    😉

  • July 28, 2010 at 2:51 am

    #1199118

    jezza101 (7/28/2010)

    sudhakara (7/28/2010)

    But i dont know why only 4 GB can able to access even if i have 6 GB of RAM in my system.

    You might find the answer here.

    😉

    Hi,

    Thanks for way that you mentioned in ur reply. I always belive that forum experts can give better solution for my questions and they can clear my doubts in good way thats the reason i am posting my quesiton on forum.

  • July 28, 2010 at 7:43 am

    #1199237

    sudhakara (7/28/2010)

    jezza101 (7/28/2010)

    sudhakara (7/28/2010)

    But i dont know why only 4 GB can able to access even if i have 6 GB of RAM in my system.

    You might find the answer here.

    😉

    Hi,

    Thanks for way that you mentioned in ur reply. I always belive that forum experts can give better solution for my questions and they can clear my doubts in good way thats the reason i am posting my quesiton on forum.

    The biggest problem in a forum, any forum, is that people sometimes want to get an answer without doing a minimal effort in searching first. If you look at the sheer number of duplicate postings you will understand what I mean.........

    _______________________________________________________________________
    For better assistance in answering your questions, click here[/url]

  • July 28, 2010 at 7:47 am

    #1199240

    Richard M. (7/28/2010)

    sudhakara (7/28/2010)

    jezza101 (7/28/2010)

    sudhakara (7/28/2010)

    But i dont know why only 4 GB can able to access even if i have 6 GB of RAM in my system.

    You might find the answer here.

    😉

    Hi,

    Thanks for way that you mentioned in ur reply. I always belive that forum experts can give better solution for my questions and they can clear my doubts in good way thats the reason i am posting my quesiton on forum.

    The biggest problem in a forum, any forum, is that people sometimes want to get an answer without doing a minimal effort in searching first. If you look at the sheer number of duplicate postings you will understand what I mean.........

    Yes. i understood but i will post questions only if i could not find correct solution and not satisfied with answer.

  • July 28, 2010 at 9:50 am

    #1199327

    Hi Sudhakara,

    From what I remember ..

    On 32-bit windows every application will be granted 4 GB Virtual Address space (VAS) not Physical Memory of 4GB. Then the VAS memory will be mapped to the available physical memory.

    So the memory limitation is from the VAS not from the available physical memory.

    On windows by default any application can use only upto 2 GB and the remaining 2GB is used by OS.

    So if you use /3 GB swith Apps can use upto 3GB and OS has only 1GB.

    So for SQL Server use more than 3GB and <=4GB, AWE has to be enabled.

    So if you have 16 GB of physical ram and If OS is using 4GB, then utmost 3 apps can be running by using 4GB RAM by mapping their VAS to 4GB physical RAM ( I.E 4X3 = 12 + 4 GB = 16 GB )

    No app can use more than 4GB even if additional memory is available.

    To overcome this limitation, you have to switch to 64-bit Os.

    Thank You,

    Best Regards,

    SQLBuddy

  • July 29, 2010 at 10:35 am

    #1199920

    232 = 4,294,967,296 = 4GB

    -MarkO

    "You do not really understand something until you can explain it to your grandmother" - Albert Einstein

  • July 29, 2010 at 10:44 am

    #1199929

    sqlbuddy123 (7/28/2010)

    Hi Sudhakara,

    From what I remember ..

    On 32-bit windows every application will be granted 4 GB Virtual Address space (VAS) not Physical Memory of 4GB. Then the VAS memory will be mapped to the available physical memory.

    So the memory limitation is from the VAS not from the available physical memory.

    On windows by default any application can use only upto 2 GB and the remaining 2GB is used by OS.

    So if you use /3 GB swith Apps can use upto 3GB and OS has only 1GB.

    So for SQL Server use more than 3GB and <=4GB, AWE has to be enabled.

    So if you have 16 GB of physical ram and If OS is using 4GB, then utmost 3 apps can be running by using 4GB RAM by mapping their VAS to 4GB physical RAM ( I.E 4X3 = 12 + 4 GB = 16 GB )

    No app can use more than 4GB even if additional memory is available.

    To overcome this limitation, you have to switch to 64-bit Os.

    Thank You,

    Best Regards,

    SQLBuddy

    Hi SqlBuddy,

    Thanks for your elaborate reply.but still i have some doubt on your reply.

    On 32-bit windows every application will be granted 4 GB Virtual Address space (VAS) not Physical Memory of 4GB.

    Do you say each process can use up to 4GB virtual address space or total server can use 4 GB virtual address space ?

    Thanks in Advance.

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