The Real World: Implementing AWE

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The Real World: Implementing AWE

Kenneth Igiri

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May 15, 2012 at 11:46 pm

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Comments posted to this topic are about the item The Real World: Implementing AWE
Br. Kenneth Igiri
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Doug Elwood-471888 SSC Eights! Points: 953 More actions · Answer 1

Good article with a few insights:

/PAE does not do anything for a 64-bit Windows O/S.

http://msdn.microsoft.com/en-us/windows/hardware/gg487503

Also, the 32-bit address space limit is 4GB, not 2GB.

2^32 = 4294967295

AWE really helps performance on SQL 2000 too.

You might want to think about upgrading to the 64-bit version of SQL 2005, it is why one of my previous employers upgraded to SQL 2005. Depending on your current SQL license, it might not restrict you to 32-bit.

M&M SSC-Insane Points: 21700 More actions · Answer 2

M&M

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May 16, 2012 at 2:01 am

#1488223

Good job, very helpful article.

M&M

heymiky SSCarpal Tunnel Points: 4875 More actions · Answer 3

Unless your running Enterprise or Data Center editions of your Server OS

MVDBA (Mike Vessey) SSC-Insane Points: 21797 More actions · Answer 4

a usefull insight into the impact - there are many detailed articles on this, but none that are as simple and clear....

one thing you missed though... your server has 32GB... what if i had between 4 and 8GB of RAM? - the use of the /3GB switch in boot.ini becomes relevant then

MVDBA

Feeg SSCrazy Points: 2766 More actions · Answer 5

(/3GB reduces the kernal memory to 1 GB and increases the user memory to 3 GB (instead of the normal 2 and 2).
/PAE enables the windowing memory functions so that apps can address more than 2 GB of memory.
As the total amount of memory on the box increases, so the kernal needs more memory to keep track of the memory allocations. If you reduce the kernal's memory to 1 GB on a box with more than 8, you could easily end up with the OS kernal starved for memory.
/pae is only needed if you have more than 4 GB memory on the server. If you're using /pae (and AWE within SQL) you should not have /3GB enabled.
)

saved this from a DBA on this forum ... think it was Gail Shaw

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jshurak SSCrazy Points: 2763 More actions · Answer 6

Doug Elwood-471888 (5/16/2012)
Also, the 32-bit address space limit is 4GB, not 2GB.

In a 32bit OS environment, 2GB is reserved for Kernel mode, and the other 2 is reserved for user mode. Though the article is a bit confusing as the author makes references to both 32bit OS (when the author describes VAS) and 64bit OS (when the author describes the boot.ini.)

Kenneth Igiri SSCarpal Tunnel Points: 4998 More actions · Answer 7

Doug Elwood-471888 (5/16/2012)
Good article with a few insights:
/PAE does not do anything for a 64-bit Windows O/S.
http://msdn.microsoft.com/en-us/windows/hardware/gg487503
Also, the 32-bit address space limit is 4GB, not 2GB.
2^32 = 4294967295
AWE really helps performance on SQL 2000 too.
You might want to think about upgrading to the 64-bit version of SQL 2005, it is why one of my previous employers upgraded to SQL 2005. Depending on your current SQL license, it might not restrict you to 32-bit.

Yo are correct in a sense. It is 4 GB but 2GB is reserved for the OS by default. So SQL Server lists its VAS as 2GB of 32-bit platform without AWE enbled.