Wednesday, October 15, 2008

Enabling AWE Memory for SQL Server

<> In SQL Server 2000 Standard or Enterprise Edition under windows 2000 or any version and server has 4GB or less ram then AWE Enabled option should always be default value of 0 which means that AWE(Advanced Windowing Extensions)  is not being used.
  
<> The AWE allows applications to run under Windows 2000 Advanced Server or Windows 2000 Datacenter Server to access more than 4GB of RAM. 

<> SQL Server 2000 Enterprise Edition (not SQL Server 2000 Standard Edition) is AWE-enabled and can take advantage of RAM in a server over 4GB.

<> If the operating system is Windows 2000 Advanced Server, SQL Server 2000 Enterprise Edition can use up to 8GB of RAM. If the operating system is Windows 2000 Datacenter Server, SQL Server 2000 Enterprise can use up to 64GB of RAM.

<> By default, if a physical server has more than 4GB of RAM, Windows 2000 (Advanced and Datacenter), along with SQL Server 2000 Enterprise Edition, cannot access any RAM greater than 4GB. In order for the operating system and SQL Server 2000 Enterprise Edition to take advantage of the additional RAM, two steps must be completed.

<> Exactly how you configure AWE memory support depends on how much RAM your server has. To configure Windows 2000 (Advanced or Datacenter), you must enter one of the following switches in the boot line of the boot.ini file, and reboot the server:
  • 4GB RAM:  /3GB (AWE support is not used)
  • 8GB RAM:  /3GB /PAE
  • 16GB RAM:  /3GB /PAE
  • 16GB + RAM:  /PAE
<> The /3GB switch is used to tell SQL Server to take advantage of 3GB out of the base 4GB of RAM that Windows 2000 supports natively. If you don’t specify this option, then SQL Server will only take advantage of 2GB of the first 4GB of RAM in the server, essentially wasting 1GB of RAM.

<> Once the above step is done, the next step is to set the “awe enabled” option to 1 within SQL Server Enterprise Edition, and then restart the SQL Server service. Only at this point will SQL Server be able to use the additional RAM in the server.

<> Think you configure the appropriate hardware and software, AWE support is not turned automatically on, you have to do this step manually. To turn AWE support on, you must change the “awe enabled” advanced SQL Server 2000 option from 0 to 1. For example, to turn on AWE support:

SP_CONFIGUREshow advanced options’, 1
RECONFIGURE                             
GO

SP_CONFIGUREawe enabled’, 1
RECONFIGURE
GO

<> To set the maximum amount of memory that AWE memory can access, you can use SQL Server’s “max server memory” configuration option. For example:

SP_CONFIGUREmax server memory’, 4096
RECONFIGURE
GO 

<> Microsoft considers AWE a premium feature, so it is not offered in all the versions of Windows 2000 and SQL Server 2000. Below is a chart showing the various versions of Windows 2000 and SQL Server 2000 that supports AWE memory.


SQL server memory. awe memory. awe switch. sql server 2000. sql server 2005. sql server 2008. awe enable. memory enable. memory configuration in sql server. sql enable. Enabling AWE Memory for SQL Server. Managing AWE Memory. in sql server 2012. SQL Server 2005 and AWE Memory. SQL Server 2008 and AWE Memory. SQL Server 2012 and AWE Memory. SQL Server AWE memory configuration. Using AWE Memory in SQL Server 2000. AWE Memory and Lock Pages in Memory. Address Windowing Extensions. awe enabled Option. Lock Pages in Memory. SQL Server allocates AWE memory while option. How to configure SQL Server to use more than 2 GB of physical memory. Not all memory is available when AWE is enabled. Why SQL Server is using so LESS memory.

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