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Enabling LPIM and AWE Expand / Collapse
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Posted Monday, April 14, 2014 6:48 AM
Grasshopper

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I'm attempting to enable AWE on SQL Server 2005 SP2 Standard but have read there may/may not be other items to enable first depending on the version.

I know I have to first enable lock pages in memory. I have sql running via the local system account so I don't think I need to add any users to the group policy correct? I also read that I need to enable trace flag 845 during startup or else it won't work? And that SP3 with CU4 is required for this to actually function in the Standard edition? There doesn't seem to be any official MSDN documents referencing any of this, but other DBA's mention this process.

Even with none of this done, if I set AWE to enabled, I actually get an "Address Windowing Extensions Enabled" message which contradicts what some of the DBA's are saying is required.
Post #1561455
Posted Monday, April 14, 2014 6:54 AM


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What's the exact version you're working with (output of SELECT @@version)?


Gail Shaw
Microsoft Certified Master: SQL Server 2008, MVP
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Post #1561456
Posted Monday, April 14, 2014 7:22 AM
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Microsoft SQL Server 2005 9.00.3042.00
Post #1561466
Posted Monday, April 14, 2014 7:23 AM


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And you left out the main piece I was interested in.

x86 or x64? Is the OS x86 or x64? If you're not sure, just post the output of SELECT @@Version



Gail Shaw
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Post #1561467
Posted Monday, April 14, 2014 7:27 AM
Grasshopper

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It's on a closed network so direct copy and paste is kind of a pain unless its a full log or something. But yeah its x86. Both SQL (standard) and windows server 2003 (standard) are 32bit versions.
Post #1561469
Posted Monday, April 14, 2014 11:07 AM
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mlwiller2 (4/14/2014)
I'm attempting to enable AWE on SQL Server 2005 SP2 Standard but have read there may/may not be other items to enable first depending on the version.

I know I have to first enable lock pages in memory. I have sql running via the local system account so I don't think I need to add any users to the group policy correct? I also read that I need to enable trace flag 845 during startup or else it won't work? And that SP3 with CU4 is required for this to actually function in the Standard edition? There doesn't seem to be any official MSDN documents referencing any of this, but other DBA's mention this process.

Even with none of this done, if I set AWE to enabled, I actually get an "Address Windowing Extensions Enabled" message which contradicts what some of the DBA's are saying is required.


AWE is independent of LPIM. What's your actual issue and how much memory do you have on the server ?

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Post #1561579
Posted Monday, April 14, 2014 11:12 AM
Grasshopper

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4Gb memory total on the sever. I have several databases over 20Gb that I can see SQL can't hold in RAM since the page life expediency time drops to near zero.

It looked like LPIM was required in order to have AWE work correct, but that may only apply to x64 systems? The documentation of differences between x86/x64 for enabling AWE seems pretty vague. However, in my test VM, all I did was enable /PAE and AWE using the GUI and it can see the AWE_Enabled run flag is "1" in the advanced options query.

I was thinking all of the other steps like updating to SP3, running trace flag 845, etc... only applied to x64 versions for AWE but I wanted to make sure.
Post #1561583
Posted Monday, April 14, 2014 11:29 AM
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mlwiller2 (4/14/2014)
4Gb memory total on the sever. I have several databases over 20Gb that I can see SQL can't hold in RAM since the page life expediency time drops to near zero.

It looked like LPIM was required in order to have AWE work correct, but that may only apply to x64 systems? The documentation of differences between x86/x64 for enabling AWE seems pretty vague. However, in my test VM, all I did was enable /PAE and AWE using the GUI and it can see the AWE_Enabled run flag is "1" in the advanced options query.

I was thinking all of the other steps like updating to SP3, running trace flag 845, etc... only applied to x64 versions for AWE but I wanted to make sure.


AWE is useful only on 32 bit systems not on 64-bit ones. And both PAE and AWE will work only if the server memory is > 4GB.

So in your case enable \3GB switch to enable SQL to use upto 3GB of memory. On 32 bit systems, if there are memory pressures then SQL server will be forced to release meomory for the OS to use.

Yeah, LPIM requires SQL Server 2005 SP3 CU4 for std edition.

Basically, LPIM is used to lock SQL Server pages in memory and to prevent paging. AWE is to extend the SQL Server memory usage beyond 4 GB.

For your case even though AWE says enabled, it won't come into affect.

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Post #1561589
Posted Monday, April 14, 2014 11:32 AM
Grasshopper

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Forgot to mention that I had planned on adding an additional 16gb for a total of 20gb to take advantage of AWE. So is LPIM not a requirement for AWE to function (just a recommendation)? All 32bit I'm working with.

I have SQL running using the local system account so what query statement could I use to check and see if LPIM was currently being used?
Post #1561592
Posted Monday, April 14, 2014 11:50 AM
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mlwiller2 (4/14/2014)
Forgot to mention that I had planned on adding an additional 16gb for a total of 20gb to take advantage of AWE. So is LPIM not a requirement for AWE to function (just a recommendation)? All 32bit I'm working with.

I have SQL running using the local system account so what query statement could I use to check and see if LPIM was currently being used?


Sorry, looks like LPIM is needed before enabling AWE. I'm not sure why MS interlinked both of these settings.

So, if you plan on adding 16GB then enable PAE switch, LPIM and then AWE. LPIM helps you preventing the paging of SQL Server.

Use the following query ..

exec xp_readerrorlog 0, 1, 'locked pages' 

The O\P of the query should contain the text

Using locked pages for buffer pool


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Post #1561603
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